Graphene2016 abstracts book

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OREWORD

On behalf of the Organising and the International Scientific Committees we take great pleasure in welcoming you to Genoa for the sixth edition of the Graphene and 2D Materials International Conference & Exhibition.

Over the past 5 editions, the Graphene Conference strengthened its position as the main meeting point of the Graphene community Worldwide.

Graphene2016 will feature:  A plenary session with internationally renowned speakers  An industrial forum focused on Graphene Commercialization  Extensive thematic workshops in parallel (Metrology, Characterization & Standardization, Health & Medical Applications, Theory & Simulation, Production & Applications of graphene and related materials, Energy and Worldwide Graphene Initiatives, Funding & Priorities)  An important exhibition carried out with the latest Graphene trends  A Brokerage event Graphene2016 is now an established event, attracting global participants intent on sharing, exchanging and exploring new avenues of graphene-related scientific and commercial developments.

We are also indebted to the following Scientific Institutions, Companies and Government Agencies for their help and/or financial support: Phantoms Foundation, Go Foundation, AIXTRON, Thermo Scientific, Aldrich Materials Science, Grafoid, Texas Instruments, Istituto Italiano di Tecnologia – Graphene Labs, Luigi Bandera spa, GDRI: Graphene-Nanotubes, GALAPAD, Springer Verlag GmbH, APS Physics, Materials Horizons journal, Cambridge University Press, Wiley, De Gruyter and Convention Bureau Genova.

We also would like to thank all the exhibitors, speakers and participants that join us this year.

We truly hope that Graphene2016 serves as an international platform for communication between science and business.

Hope to see you again in the next edition of Graphene2017 to be held in Barcelona (Spain).

Graphene2016 Organising Committee

Graphene2016

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COMMITTEES SPONSORS EXHIBITORS SPEAKERS LIST ABSTRACTS POSTERS LIST

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OMMITTEES Organising Committee Phantoms Foundation (Spain)

Antonio Correia

Université Catholique de Louvain (Belgium)

Jean-Christophe Charlier

ICREA/ICN2 (Spain)

Stephan Roche

IIT, Graphene Labs (Italy)

Francesco Bonaccorso

International Scientific Committee National University of Singapore (Singapore) IIT, Graphene Labs (Italy)

Antonio Castro Neto Vittorio Pellegrini

University of Texas at Austin (USA)

Deji Akinwande Aldo Di Carlo Sung-Yool Choi Luigi Colombo Gianaurelio Cuniberti Erik Dujardin Xinliang Feng Andrea Ferrari Mar García Hernández Jose A. Garrido Antti-Pekka Jauho Jari Kinaret Young-Hee Lee Lance Li Zhongfan Liu Vittorio Morandi Seongjun Park Marcos Pimenta Maurizio Prato Nicola Pugno C.N.R. Rao Wencai Ren Matthias Schwab Simon Xiao

University of Roma (Italy) KAIST (Korea) Texas Instruments (USA) Technische Universität Dresden (Germany) CEMES (France) Technische Universität Dresden (Germany) Cambridge University (UK) ICMM-CSIC (Spain) ICREA/ICN2 (Spain) DTU (Denmark) University of Chalmers (Sweden) SKKU (Korea) KAUST (Saudi Arabia) Peking University (China) CNR (Italy) SAMSUNG (Korea) Universidade Federal de Minas Gerais (Brazil) University of Trieste (Italy) University of Trento (Italy) JNCASR (India) Shenyang National laboratory (China) BASF (Germany) CGIA (China)

Graphene2016

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PONSORS Diamond Sponsor

www.gofoundation.ca

GO Foundation

Initiated in 2014, the is the world’s first private technology foundation dedicated to accelerate the time to commercialization of graphene-related technologies – on a globally accessible basis – while serving as a permanent fixture at the center of graphene innovation.

Platinum Sponsor

www.aixtron.com

AIXTRON is a leading provider of deposition equipment to R&D and the semiconductor industry. The Company's technology solutions are used by a diverse range of customers worldwide to build advanced components for electronic and opto-electronic applications based on compound, silicon, or organic semiconductor materials, as well as graphene, carbon nanotubes (CNT) and other 2D/1D nanomaterials. Our equipment are used today to manufacture high performance thin films for fiber optic communication systems, wireless and mobile telephony applications, optical and electronic storage devices, computing, displays, signaling and lighting.

Silver Sponsors

www.thermoscientific.com

www.sigmaaldrich.com

Lanyards Sponsor

www.grafoid.com

Graphene2016

April 19-22, 2016 Genoa (Italy)

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Other Sponsors

Awards Sponsors

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April 19-22, 2016 Genoa (Italy)

Graphene2016

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XHIBITORS

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Graphene2016

April 19-22, 2016 Genoa (Italy)

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Graphene in Spain Pavilion

China Innovation Alliance of the Graphene Industry (CGIA) Pavilion

Malaysia Pavilion

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Graphene2016

April 19-22, 2016 Genoa (Italy)

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PEAKERS LIST

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

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Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

peakers

alphabetical order PAGE Rezal Khairi Ahmad (NanoMalaysia, Malaysia) NanoMalaysia - National Graphene Action Plan 2020 Jong-Hyun Ahn (Yonsei University, Korea) Graphene based wearable electronics Adha Sukma Aji (Kyushu University, Japan) All Two-Dimensional Transparent and Flexible Transistor based on WS2 and Few-Layer Graphene Alberto Ansaldo (Istituto Italiano di Tecnoloiga, Italy) High yield production of large size few layer 2D crystals dispersions by wet-jet milling Claudia Backes (University of Heidelberg, Germany) Wet chemical functionalisation of transition metal dichalcogenides Adrian Balan (University of Pennsylvania, USA) The effect of defects on the electrical and phonon properties of graphene and MoS2 Laura Ballerini (SISSA, Italy) Graphene oxide nanosheets reshape synaptic function in cultured brain networks Ana Ballestar (Graphene Nanotech, GPNT, Spain) Graphene grown on SiC substrates for applications in electronics Luis Baptista-Pires (ICN2, Spain) Water Activated Graphene Oxide Transfer Using Wax Printed Membranes for Fast Patterning of a Touch Sensitive Device Matteo Barbone (University of Cambridge, United Kingdom) Electrically-driven quantum light emission in transition-metal dichalcogenides Sagar Bhandari (Harvard University, USA) Electron trajectories for magnetic focusing in graphene Gérard Bidan (UGA & CEA-Grenoble, France) Si-grown vertically aligned graphene nanosheets electrodes for high performance micro-supercapacitors using ionic liquid electrolytes Miriam Boehmler (neaspec GmbH, Germany) Improving graphene-based devices: New developments studied on the nanoscale via nano-FTIR microscopy and spectroscopy Peter Bøggild (Technical University of Denmark, Denmark) Large-area electrical characterisation of graphene Paolo Bondavalli (Thales, France) Graphene based supercapacitors: results and perspectives Andres R. Botello Méndez (Université Catholique de Louvain, Belgium) Atypical exciton-phonon interactions in WS2 andWSe2 monolayers: an ab-initio study

Graphene2016

Invited Workshop4

24 25

Oral Parallel PhD

26

Oral Workshop4

29

Oral Plenary

31

Oral Plenary

33

Oral Workshop2

34

Oral Industrial Forum

35

Oral Parallel PhD

37

Oral Parallel PhD

38

Oral Plenary

40

Oral Workshop5

42

Oral Workshop1

44

Invited Workshop1 Invited Industrial Forum

46 48

Oral Plenary

50

April 19-22, 2016 Genoa (Italy)

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Invited Workshop6

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Barry Brennan (National Physical Laboratory, United Kingdom) Metrology for Graphene and 2-D Materials: Characterisation and Standardisation for an Emerging Industry Andrea Candini (Istituto Nanoscienze - CNR, Italy) Ultra high photoresponsivity with field effect control in a graphene nanoribbon device Francesco Carraro (University of Padua, Italy) Fast One-Pot Synthesis of MoS2/Crumpled Graphene p–n Nanonjunctions for Enhanced Photoelectrochemical Hydrogen Production Antonio H. Castro Neto (National University of Singapore, Singapore) 2D Materials: science and technology Pietro Cataldi (Italian Institute of Technology, Italy) Foldable Conductive Cellulose Fiber Networks Modified by Graphene Nanoplatelet-Bio-Based Composites Jiri Cervenka (Institute of Physics of the Czech Academy of Sciences, Czech Republic) DNA Detection Using Graphene Field-Effect Transistors Gordon Chiu (Grafoid Inc., Canada) Graphene Developments from Raw Graphite into Industrial Partnerships Seungmin Cho (Hanwha Techwin, Korea) Fabrication of Large Area Graphene Films and Their Applications Hyoung Joon Choi (Yonsei University, Korea) Massless Dirac fermions in potassium-doped few-layer black phosphorus Hyunyong Choi (Yonsei University, Korea) Ultrafast mid-infrared 1s intraexcitonic spectroscopy in monolayer MoS2 Sung-Yool Choi (KAIST Graphene Research Center, Korea) Graphene and 2D materials for future electronics and displays Meganne Christian (CNR-IMM, Italy) Size-controlled functional graphene foams for applications in energy storage and piezoresistive sensing Jonathan Coleman (Trinity College Dublin, Ireland) Controlling the size of liquid exfoliated nanosheets and the impact of size on applications potential Camilla Coletti (CNI@NEST, Istituto Italiano di Tecnologia, Italy) Towards a scalable synthesis of van der Waals heterostructures: from graphene on h-BN to WS2 on 2D substrates Luigi Colombo (Texas Instruments, United States) Two-Dimensional Materials Growth Joel D. Cox (ICFO-The Institute of Photonic Sciences, Spain) Quantum effects in the nonlinear response of graphene plasmons Aron Cummings (Catalan Institute of Nanoscience and Nanotechnology (ICN2), Spain) Spin dynamics, dephasing, and relaxation in clean and disordered graphene Gui-Ping Dai (Chilwee Group, China) Triangle-Shaped Graphene Domains by LP-CVD and Update of Graphene Application in Motive Power Battery Lun Dai (Peking University, China) Origin of Improved Optical Quality of Monolayer Molybdenum Disulphide Grown on Hexagonal Boron Nitride Substrate

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April 19-22, 2016 Genoa (Italy)

Oral Workshop1

51

Oral Plenary

53

Oral Parallel PhD

55

Keynote Workshop3

57

Oral Parallel PhD

58

Oral Workshop2

60

Invited Industrial Forum Invited Industrial Forum

Invited Workshop6

62 63 64 65 67

Oral Workshop5

68

Invited Plenary

70

Oral Workshop4

71

Invited Industrial Forum Oral Plenary

72 73

Oral Workshop3

75

Invited Industrial Forum

77

Oral Workshop1

79

Invited Workshop3 Oral Plenary

Graphene2016

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Anindya Das (Indian Institute of Science, India) Tunability of 1/f Noise at Multiple Dirac Cones in hBN Encapsulated Graphene Devices Antonio Esau Del Rio Castillo (Istituto Italiano di Tecnologia, Italy) Exfoliation of Black-Phosphorus in low boiling point solvents and its application in Li-ion batteries Lucia Delogu (Università degli Studi di Sassari, Italy) Graphene oxide lateral dimensions can mediate different molecular response of human immune cells Vito Di Noto (University of Padova, Italy) Graphene-supported Fe, Co, Ni carbon nitride electrocatalysts for the ORR in alkaline environment Philippe Dollfus (CNRS, France) Transport gap in vertical devices consisting of twisted graphene bilayers Mildred S. Dresselhaus (Massachusetts Institute of Technology, USA) The role of graphene in characterizing layered materials Luc Duchesne (GO Foundation, Canada) GO Foundation: the power of Private Public Partnerships Dmitri K. Efetov (Massachusetts Institute of Technology, USA) Highly sensitive hBN/graphene hot electron bolometers with a Johnson noise readout Jan Englert (WITec GmbH, Germany) Multimodal Correlative Microscopy of 2D Materials David Etayo (das-Nano, Spain) ONYX Graphene and 2D Materials Inspector Norbert Fabricius (KIT, Germany) Graphene Standardization in IEC and ISO Vladimir Falko (Manchester University, United Kingdom) Bright and dark excitons and trions in two-dimensional metal dichalcogenides Xinliang Feng (TU Dresden, Germany) Towards Synthetic Two-Dimensional Soft Materials Andrea C. Ferrari (University of Cambridge, United Kingdom) The Roadmap to Applications of Graphene, Layered Materials and Hybrid Systems Aires Ferreira (University of York, United Kingdom) Towards all-electric spintronics in graphene Oral Mikael Fogelström (Graphene Centre at Chalmers, Sweden) The Graphene Flagship Costas Galiotis (FORTH/ICE-HT, Greece) Mechanics of Suspended and Supported Graphene Hong-Jun Gao (Chinese Academy of Sciences (CAS), China) Construction of Novel 2D Atomic Crystals on Transition Metal Surfaces and Physical Properties: Graphene, Silicene, Germanene, Hafnene, PtSe2 and HfTen Khasha Ghaffarzadeh (IDTechEx, United Kingdom) Graphene 2016-2026: Markets, Technologies and Players Feliciano Giustino (University of Oxford, United Kingdom) When graphene meets perovskites

Graphene2016

Oral Plenary

81

Oral Workshop5

82

Oral Workshop2

84

Oral Workshop5

87

Oral Workshop3

89

Keynote Plenary Oral Industrial Forum

91 -

Oral Plenary

92

Oral Workshop1

Invited Workshop1

93 95 97

Invited Plenary

98

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99

Oral Industrial Forum

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100

Oral Workshop3

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101 102 103

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105

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107 109

Invited Workshop6

Invited Workshop5

April 19-22, 2016 Genoa (Italy)

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Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Yury Gogotsi (Drexel University, USA) Two-Dimensional Carbides (MXenes): Synthesis, Properties and Applications José M. Gomez-Rodriguez (Universidad Autónoma de Madrid, Spain) Controlling atomic scale magnetism on graphene using hydrogen atoms Luis Gonzalez Souto (CDTI, Spain) / Antonio Correia (Phantoms Foundation, Spain EUREKA Graphene Cluster Stijn Goossens (The Institute of Photonic Sciences, Spain) High performance graphene flexible and transparent sensor platform with application in health sensing Louis Gorintin (ENGIE, France) Graphene, an incredible innovation opportunity for a fast transformation of the energy industry Carlo Grazianetti (Laboratorio MDM, IMM-CNR, Italy) Mono and Multilayer Silicene Filed-Effect Transistors Michael Grätzel (EPFL, Switzerland) Graphene boosts performance of perovskite photovolatics.

Søren Gregersen (DTU, Denmark) Graphene with triangular perforations Gloria Guidetti (University of Bologna, Italy) New synthesis and applications of graphene based photocatalytic nanocomposites for Healthier Cities Jun-han Han (Electronics and Telecommunications Research Institute (ETRI), Korea) Organic Light-Emitting Diode Display Panel Integration Using Graphene Pixel Electrodes Ling Hao (National Physical laboratory, United Kingdom) Non-invasive Microwave Method for Extended Electrical Measurements on Graphene Masataka Hasegawa (AIST, Japan) Development of graphene and related materials in TASC and AIST Tony F. Heinz (Stanford University, USA) Optical properties of atomically thin semiconductors layers and heterostructures Dake Hu (Tsinghua University, China) Vapor Phase Growth of High Quality Monolayer MoS2 at Low Temperature Yoshihiro Iwasa (University of Tokyo, Japan) Valley Physics in Transition Metal Dichalcogenide 2D crystals Mohammad Mehdi Jadidi (University of Maryland, USA) Nonlinear Terahertz Response of Graphene Plasmons Byung Chul Jang (KAIST, Korea) Interface engineering by inserting multilayer graphene barrier electrode for low power and highly uniform polymer nonvolatile memory Houk Jang (Yonsei University, Korea) Conformal Triboelectric Nanogenerator with Graphene Electrode and Their Applications in Wearable electronics Ado Jorio (UFMG, Brazil) Metrology of defects and local temperature in graphene

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April 19-22, 2016 Genoa (Italy)

Invited Plenary

111

Oral Plenary

112

Oral Industrial Forum

-

Oral Workshop2

113

Invited Industrial Forum

115

Oral Workshop4

Oral Parallel PhD

116 118 119

Oral Parallel PhD

121

Oral Industrial Forum

123

Oral Workshop1

126

Invited Workshop6

129

Keynote Plenary

131

Oral Parallel PhD

132

Invited Plenary

134

Oral Plenary

135

Oral Parallel PhD

137

Oral Industrial Forum

138

Invited Plenary

140

Keynote Plenary

Graphene2016

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Kristen Kaasbjerg (Technical University of Denmark, Denmark) Coulomb drag in graphene-based quantum-dot heterostructures Sathukarn Kabcum (Chiang Mai University, Thailand) Highly Sensitive NO2 Gas Sensors Based on Electrolytically Exfoliated Graphene/Au-catalyzed WO3 Composite Films Martin Kalbac (UFCH JH, Czech Republic) Quantification of Defects in Bilayer Graphene by Raman spectroscopy Kibum Kang (Cornell University, United States) Atomically Thin Semiconducting Paper Panagiotis Karagiannidis (University of Cambridge, United Kingdom) Microfluidization of graphite and formulation of graphene-based conductive inks Kenry (National University of Singapore, Singapore) Highly Flexible Graphene Oxide Nanosuspension Microfluidic Tactile Sensor Sandeep Keshavan (Istituto Italiano di Tecnologia, Italy) An electrophysiological approach to understand the neural interface on micro patterned graphene Frank Koppens (ICREA/ICFO, Spain) Photons, Plasmons and Electrons meet in 2d materials Tilmar Kümmell (Universität Duisburg-Essen, Werkstoffe der Elektrotechnik and CENIDE, Germany) Control of WS2 emission properties in 2D-3D semiconductor heterojunctions by band alignment Laura Lancelotti (ENEA, Portici Research Center, Italy) Graphene/Silicon Schottky barrier solar cells Gun-Do Lee (Seoul National University, Korea) Defects in Two Dimensional Materials: Cooperative Study of HR-TEM and Simulation Joung-Hoon Lee (STANDARD GRAPHENE Co.,Ltd., Korea) Graphene Roadmap of Korea and STANDARD GRAPHENE’s Products Leonid Levitov (Massachusetts Institute of Technology, USA) Electron fluid in graphene: Energy Waves, Viscosity, Current Vortices and Negative Nonlocal Resistance Shiheng Liang (Institut Jean Lamour, France) Spin transport in molybdenum disulfide multilayer channel Elefterios Lidorikis (University of Ioannina, Greece) Modelling of graphene-based sensing devices Chwee Teck Lim (National University of Singapore, Singapore) Graphene and graphene oxide for biomedical applications: From stem cell manipulation to antimicrobial applications Xiaochi Liu (SKKU Advanced Institute of Nano Technology, Korea) High performance p-type MoS2 transistor enabled by chemical doping Zhongfan Liu (Peking University, China) 2-D Nanocarbons: Attraction, Reality and Future Tsachi Livneh (NRCN, Israel) Resonant multiphonon Raman scattering in MoS2 up to the fifth order Juan Pablo Llinas (University of California at Berkeley, USA) Field Effect Transistors with Atomically Precise Graphene Nanoribbons

Graphene2016

Oral Workshop3

141

Oral Workshop2

143

Oral Workshop1 Invited Workshop4

145 146

Oral Workshop4

147

Oral Parallel PhD

149

Oral Workshop2

150

Invited Plenary

152

Oral Workshop1

154

Oral Workshop5

156

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158

Invited Industrial Forum

160

Invited Workshop3

161

Oral Plenary Oral Plenary

162 164

Invited Workshop2

166

Oral Parallel PhD

Oral Parallel PhD

168 169 170 172

April 19-22, 2016 Genoa (Italy)

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Keynote Plenary Oral Workshop1

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Annick Loiseau (LEM, ONERA - CNRS, France) Probing spectroscopic properties of BN and black phosphorus layers Martin Lottner (Technische Universität München, Germany) Flexible Graphene Transistors for Bioelectronics Steven G. Louie (University of California at Berkeley, USA) Novel Electronic and Optical Phenomena in Atomically Thin Quasi-2D Materials Richard Martel (Université de Montréal, Canada) Exfoliated Black Phosphorus: Raman Analysis and Degradation Process in Ambient Conditions Miriam Marchena (ICFO - Institut de Ciencies Fotoniques, Spain) Direct growth of patterned graphene on dielectric and flexible substrates catalyzed by a sacrificial ultrathin Ni film Kazuhiko Matsumoto (Osaka University, Japan) Selective Detection of Human & Bird Influenza Virus by Sugar Chain Modified Graphene FET Ronan McHale (Thomas Swan & Co. Ltd., United Kingdom) Commercialising CNTs, Graphene and other 2D Nanomaterials: From the Academic Lab to the Marketplace Cécilia Ménard-Moyon (CNRS, France) Biomedical applications of graphene: from functionalisation to biodistribution and biodegradation Arben Merkoçi (ICREA/ICN2, Spain) Graphene biosensors in diagnostics Vincent Meunier (Rensselaer Polytechnic Institute, USA) Low-frequency modes, twisting- and defect-induced shifts in Raman modes in MoS2, MoSe2, and phosphorene Jannik Meyer (University of Vienna, Austria) Fabrication and analysis of defective, amorphous, deformed, strained, functionalized and stacked 2D materials via high-resolution electron and scanned probe microscopies Martin Mittendorff (University of Maryland, USA) Room Temperature THz Detection with Thin Layers of Black Phosphorus Elisa Molinari (University of Modena e Reggio Emilia, Italy) Many-body interactions and optical excitations in graphene nanostructures Nunzio Motta (Queensland University of Technology, Australia) All-carbon Solid State Supercapacitors Based on Graphene Roberto Muñoz Gómez (Instituto de Ciencia de Materiales-CSIC, Spain) Direct Growth of Graphene on Transparet Insulators: Quartz & Silica SungWoo Nam (University of Illinois, USA) Three-dimensional, Corrugated Graphene Micro-/Nano-Structures for Advanced Sensor Devices Akimitsu Narita (Max Planck Institute for Polymer Research, Germany) Bottom-Up Solution Synthesis of Graphene Nanoribbons with Tailored Widths and Edge Structures Cengiz Ozkan (University of California, USA) Graphene Materials for Advanced Energy Storage

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April 19-22, 2016 Genoa (Italy)

Oral Workshop2

175 177

Keynote Plenary

179

Invited Plenary

180

Oral Workshop4

182

Oral Workshop2

184

Oral Industrial Forum

186

Invited Workshop2

188

Invited Workshop2

190

Invited Workshop3

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194

Oral Workshop4

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Invited Workshop3

197

Oral Workshop5 Oral Parallel PhD

199 201

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Invited Plenary

Graphene2016

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Tomás Palacios (Massachusetts Institute of Technology, USA) System-Level Applications of Two-Dimensional Materials: Challenges and Opportunities Vincenzo Palermo (ISOF-CNR, Italy) Scale-dependent fragmentation mechanism of two-dimensional materials Alessandro L. Palma (CHOSE, University of Rome, Italy) Graphene-based large area dye-sensitized solar cell module Maria Pantano (University of Trento, Italy) Tensile tests on single graphene layers Ioannis Paradisanos (Foundation for Research and Technology-Hellas / Institute of Electronic Structure and Laser, Greece) Spatial Nonuniformity of WS2 Monolayers Jang-Ung Park (UNIST, Korea) Wearable Electronics Using Graphene Hybrid Nanostructures Minhoon Park Park (Yonsei University, Korea) Conformal and transparent Graphene 3-axis Sensor for artificial skin Seongjun Park (Samsung Advanced Institute of Technology, Korea) 2-Dimensional Layered Materials for Si Technology John Parthenios (FORTH, Greece) A graphene touch panel display: The mechanical effect Alessandro Pecchia (CNR-ISMN, Italy) Strain engineering of thermal transport in two-dimensional grain boundaries Hailin Peng (Peking University, China) New two-dimensional crystals: controlled synthesis and optoelectronic devices Alain Pénicaud (Université de Bordeaux - CNRS - CRPP, France) Additive Free, Single Layer Graphene in Water Javier Pérez (AVANZARE, Spain) Graphene materials for energy and composites applications Marcos Pimenta (Universidade Federal de Minas Gerais, Brazil) Resonance Raman spectroscopy in novel 2D structures Eva A. A. Pogna (Politecnico di Milano, Italy) Non equilibrium optical properties of monolayer MoS2 probed by ultrafast spectroscopy Wilfrid Poirier (Laboratoire National de métrologie et d'Essais, France) A convenient quantum Hall resistance standard in graphene devices: performance and physics Marco Polini (IIT, Graphene Labs, Italy) Current-driven non-reciprocal plasmons in graphene Elena Polyakova (Graphene 3D Lab, USA) Next Generation of Nano-Enhanced Composites and 3D Printable Materials Si Qin (Deakin University, Australia) N-doped Mesoporous Molybdenum Disulfide Nanosheets: Synthesis and Application in Lithium Ion Batteries Sebastiano Ravesi (STMicroelectronics, Italy) Fabrication of Smart Systems on Flexible Substrates Enabled by Graphene Integration

Graphene2016

Invited Plenary

208

Invited Workshop4

210

Oral Parallel PhD Oral Plenary

212 214

Oral Parallel PhD

215

Oral Plenary

217

Oral Parallel PhD

218

Invited Industrial Forum Oral Workshop1

220 221

Oral Workshop3

223

Oral Workshop4

225

Oral Plenary

Invited Workshop1

226 227 229

Oral Plenary

230

Oral Workshop1

232

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Invited Industrial Forum

235

Oral Workshop5

236

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237

Oral Industrial Forum

April 19-22, 2016 Genoa (Italy)

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Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Wencai Ren (IMR-CAS, China) From Graphene to 2D Transition Metal Carbides: Synthesis and Applications Venkatesan Renugopalakrishnan (Harvard Medical School and Northeastern University, USA) Graphene Protein Microfluidic FET Sensors Curt A. Richter (National Institute of Standards and Technology, USA) Metrology for graphene, and graphene for metrology Juha Riikonen (Aalto University, Finland) Experimental and Theoretical Investigation of Highly Tunable GrapheneGaSe Field-Effect Devices with Dual Heterojunction Jonathan Roberts (Lancaster University, United Kingdom) Two-dimensional Materials as Optically Unique Identifiers Joshua A. Robinson (The Pennsylvania State University, USA) Growing Vertical in the Flatland Aleksandr Rodin (National University of Singapore, Singapore) Electronic Properties of Transition Metal Monochalcogenides Daniel Rodrigo (École Polytechnique Fédérale de Lausanne, Switzerland) Graphene as Enabling Material for Infrared Plasmonic Biosensors Marco Romagnoli (CNIT, Italy) Graphene Integrated Photonics for Next Generation Optical Communications Paolo Samori (Université de Strasbourg & CNRS, France) Supramolecular approaches to 2-D materials: from complex structures to sophisticated functions Haofei Shi (Chinese Academy of Sciences, China) Graphene Film Mass Production and Application in Distributed Flexible Sensors Jing Shi (University of California, USA) Proximity induced ferromagnetism and spin-orbit coupling in graphene Gwang Hyuk Shin (Korea Advanced Ins. of Science & Tech., Korea) Multilevel resistive switching memory based on two dimensional materials using simple solution process Marianna Sledzinska (ICN2, Spain) Thermal and elastic properties of MoS2 nanosheets Kristian Sommer Thygesen (DTU Physics, Denmark) Ab-initio calculations and simple models of electronic excitations in 2D materials and heterostructures Justin Song (Institute of High Performance Computing, Singapore) Chiral Plasmons Without Magnetic Field Ajay Kumar Sood (Indian Institute of Science, India) Photophysics of 2D Nanosystems: Raman and Ultrafast Pump-Probe Spectroscopy Ajay Kumar Sood (Indian Institute of Science, India) Overview of 2D Nanomaterials Research in India Karthik Sridhara (Texas A&M University, USA) Growth of CVD-graphene on thermally annealed and electropolished Cu substrates Mateti Srikanth (Deakin Univeristy, Australia) V2O5/graphene hybrid as superior cathode for lithium-ion batteries

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April 19-22, 2016 Genoa (Italy)

Invited Plenary

238

Invited Workshop2

240

Invited Workshop1

241

Oral Workshop4

243

Oral Parallel PhD

Oral Workshop2

245 247 248 249

Invited Industrial Forum

251

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253

Invited Industrial Forum

255

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257

Oral Parallel PhD

259

Oral Workshop1

260

Invited Workshop3

261

Oral Workshop3

263

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264

Invited Workshop6

266

Oral Parallel PhD

267

Oral Parallel PhD

269

Invited Workshop4 Oral Workshop3

Graphene2016

Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Yury Stebunov (Moscow Institute of Physics and Technology, Russia) Graphene oxide linking layers: a versatile platform for biosensing Nathaniel Stern (Northwestern University, USA) Optical Properties of Laterally-Confined Monolayer Semiconductors Jia-Tao Sun (Institute of Physics, Chinese Academy of Sciences, China) Gate Tunable Nonlinear Rashba spin splitting in transition metal dichalcogenide monolayers Nikodem Szpak (University Duisburg-Essen, Germany) Current flow paths in deformed graphene: from quantum transport to classical trajectories in curved space Alexandr Talyzin (Umea University, Sweden) High surface area graphene-related materials for hydrogen storage Cheng Tang (Tsinghua University, China) Hierarchical Porous Graphene: CVD Growth on Metal Oxides for HighRate Lithium-Sulfur battery and Superior Oxygen Evolution Electrocatalysis Alexey Tarasov (BioMed X Innovation Center, Germany) Field-effect transistors for rapid on-site disease diagnostics Sergio O. Valenzuela (ICREA/ICN2, Spain) Spin relaxation anisotropy in graphene Mutta Venkata Kamalakar (Uppsala University, Sweden) Room temperature long distance spin transport in chemical vapor deposited graphene Leonardo Vicarelli (Delft University of Technology, The Netherlands) In-situ electrical measurements of Graphene Nanoribbons fabricated through Scanning Transmission Electron Microscopy Miriam Vitiello (CNRNANO, Italy) Terahertz Nano-detectors Exploiting Novel Two-Dimensional Materials and Van der Waals Solids Thomas Weitz (LMU Munich, Germany) Electrical Characteristics of Field-Effect Transistors based on Chemically Synthesized Graphene Nanoribbons Christian Wenger (IHP GmbH - Leibniz Institute for Innovative Microelectronics, Germany) Dielectric-Graphene and Silicon-Graphene integration for GrapheneBased Devices Dongmok Whang (SKKU, Korea) Catalytic growth of 2D carbon monolayer with controlled crystallinity: from amorphous to single-crystalline Achim Woessner (ICFO - The Institute of Photonic Sciences, Spain) Broadband electrical detection of propagating graphene plasmons Marcus Worsley (Lawrence Livermore National Laboratory, USA) 3D Printing of Ultra-Compressible, Highly Conductive Graphene Aerogels Chong-Rong Wu (Academia Sinica, Taiwan) The Growth Mechanisms and Device Applications of Large-area MoS2 Films Prepared by Sulfurization of Pre-deposited Molybdenum on Sapphure Substrates Yu-Shu Wu (National Tsing-Hua University, Taiwan) VOI-Based Valley Filter in Bilayer Graphene

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Workshop 1 - Metrology, Characterization and Standardization Workshop 2 - Health and medical Applications Workshop 3 - Theory and Simulation

Workshop 4 - Production & Applications of graphene and related materials Workshop 5 - Energy Workshop 6 - Worldwide Graphene Iniciatives, Funding and Priorities

PAGE Xiaoyue Xiao (China Innovation Alliance of the Graphene Industry (CGIA), China) Initiative of Graphene Commercialization in China Won Jong Yoo (Sunkyunkwan University, Korea) Homo-junction tunneling transistors formed with chemically doped twodimensional materials Shengjun Yuan (Radboud University, The Netherlands) Mesoscopic Modeling of 2D Materials Aliaksandr Zaretski (University of California, San Diego, USA) Metallic nanoislands on graphene as highly sensitive transducers of mechanical, biological, and optical signals Hua Zhang (Nanyang Technological University, Singapore) Synthesis and Applications of Novel Two-Dimensional Nanomaterials Jin Zhang (Peking University, China) Lighting up the Raman Signal of Molecules in the Vicinity of Graphene Related Materials Lijie Zhang (University of Twente, The Netherlands) A two-dimensional Dirac material on a band gap substrate: Germanene on MoS2 Bingxin Zhao (Lab of Nanoscale Biosensing and Bioimaging, School of Ophthalmology and Optometry, Wenzhou Medical University, China) Nanocomposites from Polyethylene Glycol Modified Graphene and Transferrin as Highly Targeted Antitumor Drug Carriers Xiaodong Zhuang (Dresden University of Technology, Germany) Graphene-Coupled Sandwich-like Porous Polymers for Energy Storage and Conversion Laura Zuccaro (Max Planck Institute for Solid State Research, Germany) Graphene field-effect biosensors for real-time label-free binding kinetics Krzysztof Zwolinski (Nano Carbon, Poland) Semi-automated delamination of CVD-grown graphene in Your own lab

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BSTRACTS

NanoMalaysia - National Graphene Action Plan 2020 Rezal Khairi Ahmad NanoMalaysia¸Malaysia

Graphene presents a unique opportunity for Malaysia to develop a high value economic ecosystem within its industries in line with Malaysia’s aspiration to become a high-income nation by 2020 with improved jobs and better outputs is driving the country’s shift away from “business as usual,” and towards more innovative and high value add products. Currently, Graphene is still early in its development cycle, affording Malaysian companies time to develop their own applications instead of relying on international intellectual property and licenses. Malaysia’s National Graphene Action Plan 2020 lays out a set of priority applications that will be beneficial to the country as a whole and what the government will do to support these efforts. Malaysia will focus its Graphene action plan initially on larger domestic industries (e.g., rubber) and areas already being targeted by the government for innovation such as energy storage for electric vehicles and conductive inks. In addition to benefiting from the physical properties of Graphene, Malaysian downstream application providers may also capture the benefits of a modest input cost advantage for the domestic production of Graphene.

NanoMalaysia has been appointed as the Lead Agency to execute the National Graphene Action Plan 2020, aligned with their mandate to nurture nanotechnology development and its commercialization. At this juncture, timing is the key determinant in making sure Malaysian companies has the first mover advantage to enable them to move up the value chain and gaining access to the global market. To conduct a comprehensive analysis, a wide variety of application areas for Graphene were considered. These applications were assessed for technological feasibility by 2020, total size of the opportunity globally and relevance to Malaysia. Based on these criteria, five applications were selected as initial priority focus areas for Malaysia: lithium-ion battery anodes and ultracapacitors, rubber additives, nanofluids (drilling fluids and lubricants), conductive inks, and plastic additives. Together, these applications have the potential to contribute to achieving additional gross national income impact of more than RM 20 billion and to help create 9,000 new jobs for these industries in Malaysia by 2020.

Since the launch of National Graphene Action Plan 2020 in July 2014, there are 19 companies undertaking graphene product development projects and 2 scale-up or manufacturing prospects in Malaysia.

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Graphene based wearable electronics Jong-Hyun Ahn School of Electrical & Electronic Engineering, Yonsei University, Seoul, Korea ahnj@yonsei.ac.kr

With the emergence of unusual format electronics such as flexible, stretchable and wearable devices, an effort has been made to integrate devices with various functions for providing enhanced convenience for the users. However, it is very difficult to accomplish such electronics with conventional, rigid electronic materials. Graphene possesses an extremely good mechanical property that should maintain a stable operation under a high strain, offering great electronic properties that make it a promising host for device applications. The recent advances in synthesis and fabrication technique of graphene films are expected to enable various applications for flexible, stretchable and wearable electronics. In this talk, I present the application possibility of graphene films for flexible, stretchable and wearable electronics including sensor and energy harvesting devices.

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All Two-Dimensional Transparent and Flexible Transistor based on WS2 and Few-Layer Graphene Adha Sukma Aji1, Toshiaki Shiiba1, Kenjiro Fukuda2,3, Hiroki Ago1,3,4,* 1Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan 2Thin-Film Device Laboratory, RIKEN, Saitama, Japan 3PRESTO-JST, Saitama, Japan 4Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan *ago@cm.kyushu-u.ac.jp

Two-dimensional materials, such as graphene and transition metal dichalcogenides (TMDCs), have been attracting a great deal of interest in recent years [1]. Beside of high transparency and flexibility, high carrier mobility of graphene and direct band gap of single-layer WS2 make them a good combination for future flexible and transparent opto-electronic device [2,3]. In this work, we discuss the utilization of fewlayer graphene (FLG) and WS2 to realize all 2D material photodetector. The interesting part of this study is we found that the photodetector is worked by only applying FLG as electrode without any metal electrode on the device. Flexible and transparent parylene with 1 µm thickness was used as substrate and polymer dielectric insulator as well [4]. Moreover, parylene is extremely flexible so it wraps human skin easily as shown in Figure 1a. Additionally, Figure 1b shows an example of a transparent device on glass substrate.

FLG was chosen as electrode and backgate because of its lower sheet resistance compared to singlelayer graphene. FLG and WS2 were grown by using chemical vapor deposition (CVD) method. By using Cu-Ni foil, 10-12 nm thick of FLG was synthesized with CH4 as carbon feedstock at 1050-1070 ºC. Moreover, large area single-layer WS2 was grown on cplane sapphire at 950 ºC by evaporating WO3 powder and elemental sulfur precursor at 1070-1080 ºC and 165-170 ºC, respectively. FLG electrodes were patterned and etched by employing standard photolithography and O2 etching process. After that, large-area WS2, FLG electrode, and FLG backgate were transferred onto parylene with polystyrene support.

Finally, polystyrene was stripped away by toluene bath several times.

The schematic view of our device is shown in Figure 1c. The sheet resistance of FLG is was 100 Ω/□ measured by van der Pauw method. Figures 2a and 2b represent the device performance in dark environment. The Id-Vg measurement shows field-effect mobility as high as 2 cm2 /Vs with 104 on/off ratio. Moreover, as shown in Figure 2b, the Id-Vd characteristic implies ohmic-like contact as a result of clean interface between FLG electrode and WS2 channel. Figures 3a and 3b show the device performance under visible light (532 nm). The negatively shifted charge neutrality point under illumination suggests that the generated current is mostly accumulated from photogating effect [5]. Figure 3b plots photoresponsitivity as a function of FLG backgate applied voltage. The photoresponsitivity reached 70 µA/W at Vg = 30 V. Iilluminated/Idark ratio of the device was around 15 when illuminated with 6.5 mW/cm2 light. From the photoresponsitivity result, external and internal quantum efficiency (EQE and

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IQE) value are extracted. We found that the EQE value is only around 0.12% under illumination. Such small EQE value is expected since single-layer WS2 is transparent and pass through most of the light. On the other hand, IQE value reached 9% from single-layer WS2. IQE value represent the number of charge per absorbed photons. Hence, single-layer WS2 can generate a large number of charges even though it has high transparency.

The usage of metal-free FLG electrode, good photodetection ability of single-layer WS2, and flexible parylene is expected to open new insight into novel 2D materials-based wearable opto-electronic devices.

References [1] [2] [3] [4] [5]

A. K. Geim, Science, 324 (2009) 1530.

A. K. Geim and I. V. Grigorieva, Nature, 499 (2013) 419.

M. A. Bissett, M. Tsuji, and H. Ago, Phys. Chem. Chem. Phys., 16 (2014) 11124.

K. Fukuda et. al., Nat. Commun., 5 (2014) 4417.

M. Buschema et. al., Chem. Soc. Rev., 44 (2015) 3691.

Figures

Figure 1: (a) Photograph of the 2D material device on human skin. (b) Photograph the transparent device with parylene substrate supported by glass. (c) Schematic view of the device.

Figure 2: (a) Id-Vg and (b) Id-Vg characteristics of the device in dark.

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Figure 3: (a) Id-Vg curve and (b) photoresponsitivity of the device under light illumination.

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High yield production of large size few layer 2D crystals dispersions by wet-jet milling Alberto Ansaldo, Antonio Esau Del Rio Castillo, Filiberto Ricciardella, Silvia Gentiluomo, Vittorio Pellegrini, and Francesco Bonaccorso Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, Genova, Italy alberto.ansaldo@iit.it

Efficient and scalable two-dimensional (2D) crystals production methods are urgently needed for a rapid clearing of technological hurdles towards the development of a 2D crystals-based industry, satisfying the specific needs of different application areas. Although many approaches have been demonstrated and developed [1,2], the most promising methods for large scale production of 2D crystals rely on liquid phase exfoliation (LPE) of bulk layered crystals [3,4,5]. Currently, the LPE is largely based on ultrasonication, a time consuming process [5] which is emerging as the main limitation of this method. Recently, new approaches for the full exploitation of LPE of layered crystals have been proposed, with the aim to improve the ease of production and scalability [6].

Here we propose high pressure wet-jet milling (hp-WJM, Fig. a) as a novel approach for the exfoliation of layered crystals by LPE. This technique allows us to produce bulk quantities of 2D flakes in dispersion (Fig. b). For example, by exploiting hp-WJM we scaled the production of few-layer graphene (FLG) flakes in dispersion up to over 2 L/h, with a concentration higher than 10 g/L. This dispersion is characterized by large lateral size FLG flakes (Fig. c) with low defects concentration (Raman peak intensity ratio ID/IG ≈ 0.5, Fig. d). The as-produced flakes are already suitable for many industrial applications such as polymer composites. A further processing step, i.e. purification by ultracentrifugation [7], allows the selection of the highest quality flakes, maintaining a still high concentration, i.e.,~1.1 g/L (ID/IG ≈ 0.47, g-force ~500 g).

The same method has been successfully applied to other layered crystals (e.g., BN, MoS2, WS2, WSe2, Bi2Te3, just to cite a few). Our latest results on the production and processing of 2D crystals as well as their applications in Li batteries, composites, flexible conductors will be presented.

References [1] [2] [3] [4] [5] [6] [7]

F. Bonaccorso, et al., Materials Today, 15 (2012) 564.

A. C. Ferrari, et al., Nanoscale, 7 (2015) 4598.

V. Nicolosi, et al., Science, 340 (2013) 1226419.

F. Bonaccorso, et al, Advanced Materials (2016), in press Y. Hernandez, et al., Nature Nanotechnology, 3 (2008) 563.

K. R. Paton, et al., Nature Materials, 13 (2014) 624 F. Bonaccorso, et al., J. Phys. Chem C, 114 (2010) 17267.

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Figures

Figure 1: a) Scheme of the hp-WJM process, b) 2D crystal dispersions produced by hp-WJM; c) TEM image of micron size exfoliated FLG flakes; d) Raman spectra of FLG (red) and starting graphite (black).

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Wet chemical functionalisation of transition metal dichalcogenides Claudia Backes, Andreas Hirsch, Aidan McDonald, Jonathan N. Coleman Applied Physical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany Backes@uni-heidelberg.de

Over the last few years the study of 2-dimensional (2D) nanomaterials has become one of the most important areas of both materials science and nanotechnology. While this work originally focused on graphene, the palette of 2D materials currently under study includes transition metal dichalcogenides (TMDs) such as MoS2 and WSe2, layered transition metal oxides and a host of other interesting structures. Particularly useful is the diversity of 2D materials: depending on the combination of elements and their arrangement, they can be metals, semi-conductors, insulators or superconductors. They display a range of interesting properties from thickness-dependent bandgaps to catalytic activity to the ability to act as drug delivery vehicles. These properties make them useful for both fundamental studies and applications in areas as diverse as optoelectronics, electrochemistry and medicine.

However, to tap their full potential and to combine their diverse and unique properties with those of other substance classes, methods to functionalise layered materials are sought for.

Here we present three methods to chemically functionalise the MoS2 basal planes by i) noncovalent functionalisation, ii) coordination chemistry and iii) reductive covalent functionalisation.

Noncovalent functionalisation is probably the easiest way to modify surface properties of nanomaterials in liquids. As we showed using liquid exfoliated WS2 in poly vinyl alcohol as model system,[1] noncovalent functionalisation also offers exciting possibilities to change the doping level in the TMD. In addition, the bulky stabiliser shields the exfoliated nanosheets from restacking in thin films so that monolayer properties are widely maintained. These composites offer exciting perspectives both for fundamental studies and applications.

The coordination chemistry approach [2] relies on anchoring transition metal cations such as Cu2+ or Ni2+ to the sulphur atoms of the dichalcogenide surface after liquid-phase exfoliation of the nanomaterial by established techniques. Ligands in the periphery of the transition metal cations can be replaced potentially providing a diversity of functional entities.

Critically, X-ray photoelectron spectroscopy reveals that up to 50% of the S atoms can be functionalised (maximum loading).

In addition, we show the covalent reductive functionalization of MoS2. [3] The MoS2 basal planes can be functionalised in analogy to graphene. The reaction sequence is based on intercalation of the material by n-butyl lithium to yield negatively charged MoS2 nanosheets that are exfoliated down to monolayers in water. The negative charges can subsequently be quenched by the addition of a diazonium salt to obtain covalently functionalised MoS2. In contrast to graphene, the reaction can be carried out in water under ambient conditions after the initial intercalation step.

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We expect these approaches to be applicable to other transition metal dichalcogenides giving access to a broad palette of new functional materials with modified surface properties, improved processability and yet unknown properties. Most importantly, we believe that these materials can be used as building blocks in composites and hybrid structures by further derivatisation.

References [1] [2] [3]

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Vega-Mayoral, V.; Backes, C.; Hanlon, D.; Khan, U.; Gholamvand, Z.; O'Brien, M.; Duesberg, G. S.; Gadermaier, C.; Coleman, J. N., Adv. Func. Mater. 2016, DOI: 10.1002/adfm.201503863.

Backes, C.; Berner, N. C.; Chen, X.; Lafargue, P.; LaPlace, P.; Freeley, M.; Duesberg, G. S.; Coleman, J. N.; McDonald, A. R., Angew. Chem., Int. Ed. 2015, 54 (9), 2638-2642.

Knirsch, K. C.; Berner, N. C.; Nerl, H. C.; Cucinotta, C. S.; Gholamvand, Z.; McEvoy, N.; Wang, Z.; Abramovic, I.; Vecera, P.; Halik, M.; Sanvito, S.; Duesberg, G. S.; Nicolosi, V.; Hauke, F.; Hirsch, A.; Coleman, J. N.; Backes, C. ACS Nano 2015, 9 (6), 6018–6030.

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The effect of defects on the electrical and phonon properties of graphene and MoS2 Adrian Balan1,3, Liangbo Liang2, William Parkin1, Michael Lamparski2, Paul Masih Das1, Carl H. Naylor1, Julio A. Rodriguez-Manzo1, Matthew Puster1, A.T. Charlie Johnson, Jr.1, Vincent Meunier2, Marija Drndić1 1Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA 2Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA 3 CEA Saclay, LICSEN, France adrian.balan@gmail.com

We present a comprehensive study of the effects of the defects produced by electron irradiation on the electrical and crystalline properties of graphene and MoS2 monolayers. We realized electrical devices from monolayer MoS2 or graphene crystals suspended on a 50nm SiNx membrane. The samples are exposed to electron irradiation inside a 200kV transmission electron microscope (TEM) and we perform in situ conductance measurements [1] and subsequently ex-situ Raman cartography. We correlate the damage to the crystalline lattice - measured by diffraction - with the observed decrease in the two-terminal conductivity of the devices and the variation in the Raman phonon modes. The change in the diffraction pattern is fitted to a kinematic model. The variation of the phonon modes is fitted to DFT simulations. The evolution of the conductivity with the defect concentration is approached in the percolation theory framework, using a resistance network model.

References [1]

M. Puster, J. A. Rodriguez- Manzo, A. Balan, M. Drndic., ACS Nano, 7 (2013), pp 11283– 11289.

Figures

Figure 1: a) Schematic representation of the monolayers exposed to the electron beam. b) Increase of graphene resistance during electron irradiation c) Increase of MoS 2 resistance during electron irradiation.

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Graphene oxide nanosheets reshape synaptic function in cultured brain networks Laura Ballerini, Rossana Rauti, Neus Lozano, Denis Scaini, Mattia Musto, Ester VĂĄzquez, Kostas Kostarelos, Maurizio Prato School for Advanced Studies (SISSA) via Bonomea 265 I-34136 Trieste, Italy laura.ballerini@sissa.it

Graphene is a highly advanced metamaterial at the forefront of revolutionary applications in neurological diseases. Biomedical developments in general, and in neurology in particular, are focusing on few-layer graphene sheets to manufacture novel bio-devices, including biosensors, interfaces, tissue scaffolds, drug delivery and gene therapy vector systems. In this context, exploration of the interactions between graphene nano- and micro-sheets with the sophisticated signaling machinery of nerve cells is of great importance.

Here we explore for the first time by patch clamp and fluorescence imaging the ability of graphene (GR) and graphene oxide (GO) nanosheets to interfere with synaptic signaling once hippocampal cultured neurons are exposed for one week to a growth medium containing thin sheets of such materials at 1 or 10 Âľg/mL. We further investigated whether, in the absence of explicit cell toxicity, such materials affected the ability of astrocytes to release synaptic-like microvesicles (MV) in pure glial cultures. Our results describe the potential of GO nanosheets to alter different modes of inter-neuronal communication systems in the CNS hinting at opportunities for novel neuromodulatory applications or highlighting subtle, but potentially unwanted, subcellular interactions.

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Graphene grown on SiC substrates for applications in electronics A. Ballestar1,2, A. García-García1,3, L. Serrano1,2, J. M. de Teresa2,4,5, M. R. Ibarra2,5, P. Godignon3 1Graphene Nanotech, S.L., Miguel Villanueva 3, 26001 Logroño, Spain 2INA, LMA, Universidad de Zaragoza, Mariano Esquillor, 50018 Zaragoza, Spain 3CNM-IMB-CSIC, Campus UAB, Bellaterra, 08193 Barcelona, Spain 4ICMA, Universidad de Zaragoza, 50009 Zaragoza, Spain 5Departamento Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain ana@gpnt.es

Since the isolation of graphene became accessible and the investigation of its properties revealed outstanding features [1-2], a large number of companies aiming the production of graphene-based materials and devices appeared in order to develop a new and powerful technology. However, the fabrication process of high quality graphene in an industrial scale remains as an open issue. The growth of graphene on Silicon Carbide (SiC) wafers is one of the most promising routes for both, production and integration into planar technology electronic applications [3-5]. We fabricated epitaxial graphene on top of different types of SiC substrates. Of particular interest for electronic applications are those in which a bottom gate is ready to be used and prepared prior to graphene growth. Processes of implantation of nitrogen atoms at a controlled depth have been used in order to fabricate such substrate.

We investigated the properties of the graphene grown on top of them by means of noninvasive techniques, e.g. Raman spectroscopy and optical and atomic force microscopy (AFM), and completed the characterization with High Resolution Transmission Electron Microscopy (HRTEM) and transport measurements. As a result, we found that high quality single layer graphene is covering ~85% of the substrate and it appears to be a good candidate for the development of bottom gated devices based on graphene in an industrial scale.

References [1] [2] [3] [4] [5]

K. S. Novoselov et al., Nature, 306 (2004) 666.

K. S. Novoselov et al., Nature, 490 (2012) 192.

N. Camara et al., Appl. Phys. Lett., 93 (2008) 263102.

P. N. First, MRS Bulletin, 35 (2010) 296.

D. Waldmann et al., Nature Mat., 10 (2011) 357.

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Figures

Figure 1: Raman results obtained on graphene grown on an implated SiC substrate. On the left hand side, Raman spectra measured at the position indicated by the white cross in the picture besides.

On the right hand side, maping of the FWHM of the 2D peak, in which only the yellow dots indicate positions where single layer graphene is not found, as it can be inferred from the color scale to the right.

Figure 2: a.: Optical Image of a sample surface. Note the large width of the observed terraces.

Figure 2.b.: HRTEM image of a sample, in which the presence of one graphene layer and the buffer layer are clearly seen (dark lines on the center of the image).

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Water Activated Graphene Oxide Transfer Using Wax Printed Membranes for Fast Patterning of a Touch Sensitive Device Luis Baptista-Pires1, Carmen C. Mayorga-Martínez1, Mariana Medina-Sánchez1, Helena Montón1 and Arben Merkoçi1,2, 1Catalan

Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona, 08193, Spain 2ICREA, Barcelona, Spain Luis.pires@icn.cat

Printed electronics paved the way to a new type of low cost technologies over plastics and organic substrates for building electrical and electronic devices. We demonstrate a graphene oxide printing technology using wax printed membranes for the fast patterning and water activation transfer using pressure based mechanisms. The wax printed membranes have 50 μm resolution, longtime stability and infinite shaping capability. The use of these membranes complemented with the vacuum filtration of graphene oxide provides the control over the thickness. Our demonstration provides a solvent free methodology for printing graphene oxide devices in all shapes and all substrates using the roll-to-roll automatized mechanism present in the wax printing machine. Graphene oxide was transferred over a wide variety of substrates as textile or PET in between others. Finally we developed a touch switch sensing device integrated in a LED electronic circuit.

References [1]

Luis Baptista-Pires, Carmen C. Mayorga-Martínez, Mariana Medina-Sánchez, Helena Montón and Arben Merkoçi; ACS Nano; December 2015.

DOI: 10.1021/acsnano.5b05963.

Figures

Figure 1: a) Wax printed membranes used for patterning graphene oxide. b) Platform used for switching ON and OFF a LED.

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Electrically-driven quantum light emission in transition-metal dichalcogenides M. Barbone1, C. Palacios-Berraquero2, D. M. Khara2, X.Chen1, I. Goykhman1, M. AtatĂźre2, A. C. Ferrari1 1Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK 2Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK mb901@cam.ac.uk

Integrating single-photon sources into on-chip optical circuits is a challenge for scalable quantum-photonic technologies aiming at the ultimate goal of using single-photons for quantum information, quantum key distribution and quantum lithography[1]. Despite a plethora of single-photon sources reported to-date[2-4], all-electrical operation, critical for applications where miniaturization plays a key role, such as on-chip photonic circuits[1,5,6], has been reported for only three systems: semiconductor quantum dots[6], nitrogen vacancies in diamond[7] and SiC[8]. The attractiveness of single-photon sources in layered materials[9-13] stems from their ability to operate at the fundamental limit of single-layer thickness, with high extraction efficiency (i.e. the number of photons generated by the quantum dot minus those lost after emission due to scattering while crossing the quantum dot’s host matrix) and with the potential to integrate into conventional and scalable highspeed optoelectronic devices[14], as opposed to the single-photon emitting systems known so far, which suffer dramatically from any proximity to an interface[5]. Here we report light emitting devices realized by vertical stacking graphene, h-BN and mono- and bilayer transition-metal dichalcogenides (TMDs). We show that quantum emitters in WSe2 can operate electrically. We further report all-electrical single-photon generation in the visible spectrum from a new class of quantum emitters in WS2 (Fig. 1). Our TMD-based quantum emitters show electrically-driven single-photon generation over a ~180 nm spectrum. Our results demonstrate that layered materials are a platform for integrable and atomically precise quantum photonics device technologies.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

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L. O'Brien et al, Nat. Photonics 3 (12), 687 (2009).

J. McKeever et al., Science 303 (5666), 1992 (2004).

S. G. Lukishova et al., IEEE J. Sel. Top. Quantum Electron. 9 (6), 1512 (2003).

A. Beveratos et al., Phys. Rev. Lett. 89 (18), 187901 (2002).

M. D. Eisaman et al., Rev. Sci. Instr. 82 (7), 071101 (2011).

Z. Yuan, et al. Science 295 (5552), 102 (2002).

N. Mizuochi et al. Nat. Photonics, 6 (5), 299 (2012).

A. Lohrmann et al. Nat. Commun., 6, 7783 (2015).

A. Srivastava et al. Nat. Nanotechnol., 10 (6), 491 (2015).

Y.-M. He et al. Nat. Nanotechnol., 10 (6), 497 (2015).

M. Koperski et al. Nat. Nanotechnol., 10 (6), 503 (2015).

C. Chakraborty et al. , Nat. Nanotechnol., 10 (6), 507 (2015).

P. Tonndorf et al., Optica, 2 (4), 347 (2015).

H. Wang et al., Nat. Commun., 6, 8831 (2015)..

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Figures

Figure 1: (a) Map of the EL spectrum of electrically-driven quantum light in WS2 as a function of the applied bias displaying the evolution of the excitonic complexes and the emergence of the delocalised emission at higher bias. The spectrum at the top (bottom) of the panel is a line cut for injection current of 1.8 ÎźA (0.578 ÎźA) showing classical (quantum) light. (b) Second order correlation measurements confirm the single-photon nature of the emitters at low injection current.

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Electron trajectories for magnetic focusing in graphene S. Bhandari1, G.-H. Lee2, P. Kim1, 2 and R.M. Westervelt1, 2 1School of Engineering and App. Sciences, Harvard University Cambridge, MA 02138, U.S.A 2Department of Physics, Harvard University Cambridge, MA 02138, U.S.A sbhandar@fas.harvard.edu

Scanning Gate Microscopy (SGM) is a powerful tool for gaining insight into the local electronic properties of nanoscale devices. The charged tip of a scanned probe microscope is held just above the sample surface, creating an image charge inside the device that scatters electrons. By measuring the change in conductance while the tip is raster scanned above the sample, an image of electron motion can be obtained [1-3]. Using this technique, we previously imaged magnetic focusing in a two-dimensional electron gas (2DEG) inside a GaAs/AlGaAs heterostructure [2]. We have recently used a cooled SGM to image cyclotron orbits [3] in ballistic hBN-graphene-hBN devices in magnetic focusing regime [4]. Magnetic focusing occurs when orbits passing into the sample from one narrow contact pile together on a second contact that is located an integer number of cyclotron diameters away.

In this talk, we describe our SPM imaging technique by presenting ray-tracing trajectories of ballistic electron flow through the sample that include scattering by the image charge below the tip. The electrostatic image charge creates a density dip ntip that locally reduces the Fermi energy EF(n + ntip), creating a force F = ∇EF that pushes electrons away from the tip location. This force scatters orbits away from the receiving contact, as shown by the red traces in Fig. 1a. An experimental SPM image of the cyclotron orbit on the first magnetic focusing peak shown in Fig. 1b displays the measured change Rm in transresistance vs. tip position. A corresponding simulated image in Fig. 1c is obtained by displaying the change T in transmission caused by the presence of the tip. In the simulations, we injected 10,000 trajectories into the graphene with a uniform distribution across the width of the contact and a uniform angular distribution at each point. The simulated image (Fig. 2c) is a good match to the experimental results (Fig. 2b). This approach allows us to investigate the influence of the electron density n and magnetic field B on images of electron flow by comparing experiments with simulations. * Supported by the Dept. of Energy grant DE-FG02-07ER46422.

References [1] [2] [3] [4]

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M.A. Topinka and R.M. Westervelt et al., Nature 410, (2001) 183.

K.E. Aidala and R.M. Westervelt et al., Nature Physics 3, (2007) 464.

S. Bhandari et al., arXiv:1510.05197v3, (2015).

T. Taychatanapat and P. Jarillo-Herrero et al., Nature Physics 9, (2013) 225.

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Figures

ΔRm(Ω) 15 b

1

2

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T (%) 15 ca b b

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Figure 1: (a) Ray-tracing trajectories for B = 0.130 T and tip position (0.75 µm, 0 µm). Cyclotron-orbit trajectories are deflected by the density change beneath the tip. (b) Experimental and (c) simulated cyclotron orbit images on the first focusing peak for n = 1.29x1011 cm-2 and B = 0.130 T.

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Si-grown vertically aligned graphene nanosheets electrodes for high performance micro-supercapacitors using ionic liquid electrolytes David Aradilla, Marc Delaunay, Saïd Sadki, Jean-Michel Gérard and Gérard Bidan Univ. Grenoble Alpes, CEA/INAC, 17, rue des Martyrs, F-38000 Grenoble, France gerard.bidan@cea.fr

Over the past years, the development of innovative technological applications in the field of micro-electronics, micro-medicine or nano-engineering, has sparked a great deal of attention in the research of high performance energy storage units. Recently, tremendous efforts have been devoted to develop novel high-performance micro-supercapacitors (mSCs) based on nanostructured material electrodes with advanced architectures. From this perspective, new materials based on nanostructured silicon (e.g. silicon nanowires[1]), or nanostructured carbonaceous materials have attracted a special interest in the field of microsupercapacitor devices owing to their unique properties in terms of long cyclability and high power pulse.

Accordingly, in recent years micro-supercapacitors based on reduced graphene oxide (rGO) electrodes have been extensively investigated. However, the rGO morphology as horizontally stacked sheets parallel to the electrode surface does not allow easy diffusion of electrolyte ions. The advent of vertically oriented graphene nanosheets (VOGNs) grown by plasma deposition allowed easy and fast access of ions to the electrode [2] and made it possible to usher m-SCs into the high-frequency filtering arena with high ripple current [3].

This study reports the synthesis and application of VOGNs deposited on highly doped silicon substrates through an alternative and catalyst-free method based on electron cyclotron resonanceplasma enhanced chemical vapor deposition (ECR-CVD) technique. The graphene-based electrodes were employed in a symmetric micro-supercapacitor device using an aprotic ionic liquid (PYR13TFSI) as electrolyte, which was used owing to its moderate viscosity and wide voltage stability window (4 V) [1]. A complete and detailed electrochemical characterization of the micro-device was evaluated by cyclic voltammetry, galvanostatic charge–discharge cycles and electrochemical impedance spectroscopy.

Furthermore, an exhaustive morphological and structural characterization of the graphene electrodes was carried out by using scanning electron microscopy (fig. 1 A)), transmission electron microscopy and Raman spectroscopy.

The device was able to deliver an outstanding specific capacitance value of 2 mF cm-2, (fig.

1 B)) a power density value of 4 mW cm-2 and an energy density value of 4 mW h cm-2 operating at a large and stable cell voltage of 4 V with a quasi-ideal capacitive behaviour.

Moreover, the lifetime of the device exhibited a remarkable electrochemical stability retaining 80% of the initial capacitance after 150 000 galvanostatic charge–discharge cycles

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(fig. 1C)) at a high current density of 1 mA cm-2. These performances open the route for onchip energy storage micro-units and their integration into miniaturized electronic devices [4].

References [1] [2] [3] [4]

D. Aradilla, P. Gentile, G. Bidan, V. Ruiz, P. Gomez-Romero, T. J. S. Schubert, H. Sahin, E. Frackowiak, S. Sadki, NanoEnergy, 9 (2014) 273.

Z. Bo, S. Mao, Z. Zhao Jun Han, K. Cen, J. Chen, K. Ostrikov, Chem. Soc. Rev., 44 (2015) 2108.

J. R. Miller and R. A. Outlaw, J. Electrochem. Soc., 162 (2015) A5077.

D. Aradilla, M. Delaunay, S. Sadki, J.-M. Gérard, G. Bidan, J. Mat. Chem. A, 3 (2015) 19254.

Figures

Figure 1: A), SEM images of the cross sectional view of VOGNs deposited using a deposition time of 0.4 h (2 µm thickness) on Si substrate; B), Specific capacitance as a function of current densities (0.25 - 2 mA cm-2) and C) Lifetime testing of the devices performed using 150 000 complete charge– discharge cycles at a current density of 1 mA cm-2 between 0 and 4 V using different thicknesses of VOGNs (1 (red dot), 2 (green triangle), 6 (orange square) and 12 (blue diamond) µm respectively).

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Improving graphene-based devices: New developments studied on the nanoscale via nano-FTIR microscopy and spectroscopy Miriam Bรถhmler neaspec GmbH, Bunsenstr. 5, 82152 Munich, Germany miriam.boehmler@neaspec.com

The performance of the next-generation optoelectronic devices based on graphene is strongly influenced by the structure-function relationship. For example, a long life time of the surface plasmons is, although theoretically predicted, still lacking due to strong damping mechanisms. New ideas have thus been introduced, and they strongly demand for an analytic tool that allows to study the plasmonics behavior with nanometer resolution in real space.

With scattering-type scanning near-field microscopy (s-SNOM) such a tool has been invented, enabling the nanoscale mapping of nano-devices. It combines the best of two worlds: the high spatial resolution of atomic force microscopy (AFM) and the analytical power of infrared spectroscopy. The spatial resolution of about 10 nm of nano-FTIR microscopy opens a new era for modern nano-analytical applications such as chemical identification, free-carrier profiling and plasmonic vector near-field mapping.

Recent graphene related research will be highlighted, demonstrating the power of nano-FTIR microscopy due to its contact-free direct access to the plasmonic properties, local conductivity, electron mobility and intrinsic doping via plasmon interferometry imaging [1-4].

Using plasmon interferometry, nano-FTIR microscopy can investigate losses in graphene by exploring real-space profiles of plasmon standing waves formed between the tip of our nano-probe and the edges of the samples (fig1). Plasmon dissipation quantified through this analysis is linked to the exotic electrodynamics of graphene.

Using femtosecond light sources, s-SNOM has successfully be extended towards ultrafast experiments with up to 10-femtosecond temporal resolution. Investigation of carrierrelaxation dynamics in graphene [5] demonstrates the high potential for ultrafast near-field microscopy.

A new s-SNOM configuration even combining near-field microscopy with photocurrent nanoscopy (fig2) [6]. The symbiosis of these two complementary techniques opens up a complete new research field for nano-spectroscopy, bringing together optical, optoelectronic and electronic analysis on the nanoscale in a complete non-destructive and noninvasive way.

Beyond the mentioned examples a further overlook of the latest research will be given in this presentation.

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References [1] [2] [3] [4] [5] [6]

A Woessner et al., Nature Materials 14 (2015) 421.

S. Dai et al., Nature Nanotechnology 10 (2015) 682.

Z. Fei et al., Nature 487 (2012) J. Chen et al., Nature 487 (2012) 82.

M. Wagner et al., Nano Letters 14, (2014) 894.

A. Woessner et al., arXiv:1508.07864v1.

Figures

Figure 1: Correlative AFM and nano-FTIR microscopy. Contact-free direct access to local conductivity, electron mobility and intrinsic doping via plasmon interferometry imaging.

Figure 2: Schematic of near-field photocurrent experiment. Right: Photocurrent near-field map of a graphene sheet revealing characteristic patterns on the nanoscale. (From [6].

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Large-area electrical characterisation of graphene Peter Bøggild, Jonas Due Buron, Dirch Hjorth Petersen, David M. A. Mackenzie, Tim Booth, Peter Uhd Jepsen DTU Nanotech, Ørsteds Plads, Technical University of Denmark, Kgs. Lyngby, Denmark peter.boggild@nanotech.dtu.dk

The gap between the rapidly upscaling of large-area graphene production compared to available electrical characterisation methods could become a major roadblock for emerging graphene applications. As an alternative to the often slow, cumbersome and destructive characterisation techniques based on electrical field effect or Hall measurements, THz time-domain spectroscopy (THzTDS) [1] not only maps the conductance quickly and non-destructively, but also accurately. This is confirmed by direct comparison with micro four-point probe (M4PP) measurements, another lowinvasive, well-established method already used by major semiconductor manufacturers for inline quality control. In addition to spatial maps of the sheet conductance, THz-TDS and M4PP offer unique information on otherwise hidden defects and inhomogeneities, as well as detailed scattering dynamics in the graphene film on nm to mm length scales [2-4]. We also show that THz-TDS can be used to map the carrier density and mobility, either by transferring graphene to a substrate equipped with a THztransparent back gate [5], or by analyzing the frequency response in detail to extract the scattering time at a constant carrier density [6], which allows the mobility to be mapped even on insulating substrates. In contrast with conventional field effect and Hall measurements, THz-TDS measures the actual, intrinsic carrier mobility, i.e. not derived from a conductance (extrinsic) measurement. As field effect measurements are expected to remain useful for benchmarking, we have developed a fast (1 hour turnaround time) and clean (no solvents or water) method for converting a graphene wafer into 49 FET devices with electrical contacts, using a combination of a physical shadow mask and laser ablation [6,7]. Finally, the challenges of realizing in-line monitoring of the electrical properties in a graphene production scenario, and the prospects for establishing THz-TDS mapping as a measurement standard for largearea graphene films will be discussed.

References [1] [2] [3] [4] [5]

46

J. Buron, D. H. Petersen, P. Bøggild, D. G. Cooke, M. Hilke, J. Sun, W. Whiteway, P. F. Nielsen, O. Hansen, A. Yurgens, P. Uhd-Jepsen, Nano Letters, 12 (2012), 5074.

J. D. Buron, F. Pizzocchero, B. Jessen, T. J. Booth, P. F. Nielsen, O. Hansen, M. Hilke, E. Whiteway, P. U. Jepsen, P. Bøggild, D. H. Petersen, Nano Letters, 14 (2014), 6348.

M. R. Lotz, M. Boll, O. Hansen, D. Kjær, P. Bøggild, D. H. Petersen, Appl. Phys. Lett., 105 (2014), 053115.

M. Boll, M. R. Lotz, O. Hansen, F. Wang, D. Kjær, P. Bøggild, and D. H. Petersen, Phys.

Rev. B, 90 (2014), 245432.

J. D. Buron, D. M. A. Mackenzie, D. H. Petersen, A. Pesquera, A. Centeno, P. Bøggild, A. Zurutuza, P. U. Jepsen, Optics Express, 24 (2015), 250745.

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[6] [7]

J. D. Buron, F. Pizzocchero, P. U. Jepsen, D. H. Petersen, J. M. Caridad, B. S. Jessen, T. J. Booth, P. Bøggild, Scientific Reports 5 (2015), 12305.

D. Mackenzie, J. Buron, B. S. Jessen, A. Silajdzic, A. Pesquera, A. Centeno, A. Zurutuza, P. Bøggild and D. H. Petersen, 2D Materials, 4 (2015), 045003.

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Graphene based supercapacitors: results and perspectives Paolo Bondavalli1, Gregory Pognon2 1Head of the nanomaterial topic team, Joint unit CNRS/Thales, Physics Department, Thales Research and Technology, 91120 Palaiseau, France 2Multi-functional Material Lab, GTM department, Thales Research and Technology, 91120 Palaiseau, France

Supercapacitors are electrochemical energy storage devices that combine the high energystorage-capability of conventional batteries with the high power-delivery-capability of conventional capacitors. In this contribution we will show the results of our group recently obtained on supercapacitors with electrodes obtained using mixtures of carbonaceous nanomaterials (carbon nanotubes (CNTs), graphite, graphene, oxidised graphene). The electrode fabrication has been performed using a new dynamic spray-gun based deposition process set-up at Thales Research and Technology (patented). First, we systematically studied the effect of the relative concentrations of Multi-Walled Carbon Nanotubes (MWCNTs) and graphite on the energy and power density. We obtained a power increase of a factor 2.5 compared to barely MWCNTs based electrodes for a mixture composed by 75% of graphite. This effect is related with the improvement of the mesoporous distribution of the composites and to the increase of the conductance as pointes out by Coleman et al. After these results, we decided to test water as a solvent in order to reduce the heating temperature and to obtain a green type process without toxic solvents. To achieve stable suspensions we oxidised the graphene and the CNTs before putting them in water. We observed that changing the Graphene Oxide concentrations we obtained different value of capacitance and energy. The best results were obtained with 90% of GO and 10% of CNTs. We obtained 120F/g and a power of 30kW/Kg. The importance of these results is that it is the first time that these performances have been obtained for graphene related materials using an industrial fabrication suitable technique that can be implemented in roll-to-roll production. In this way we were able to fabricate stable suspensions in less than one hour compared to three days using NMP. All these results demonstrate the strong potential to obtaining high performance devices using an industrially suitable fabrication technique.

Finally, new results using mixtures of Carbon nanofibers and graphene will be shown. These new composite allow to use ionic liquid as electrolytes and so to increase dramatically the energy stored in the device without reducing the power.

References [1] [2]

48

Supercapacitor electrode based on mixtures of graphite and carbon nanotubes deposited using a new dynamic air-brush deposition technique, P Bondavalli, C.Delfaure, P.Legagneux, D.Pribat JECS 160 (4) A1-A6, 2013 Non-faradic carbon nanotubes based supercapacitors : state of the art, P.Bondavalli, D.Pribat, C.Delfaure, P.Legagneux, L.Baraton, L.Gorintin, J-P. Schnell, Eur. Phys. J. Appl.

Phys. 60,10401, 2012.

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Figures

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Atypical exciton-phonon interactions in WS2 and WSe2 monolayers: an ab-initio study Andrés R. Botello-Méndez, Yannick Gillet, Elena del Corro, Marcos Pimenta, Mauricio Terrones, Xavie Gonze, Jean-Christophe Charlier IMCN-NAPS, Université catholique de Louvain, Chemin des étoiles 8, 1348 Louvain-la-neuve, Belgium andres.botello@uclouvain.be

The resonant Raman spectra of single-layered WS2 and WSe2 have been measured in a wide range of energies (using more than 25 laser lines). The resulting Raman excitation profiles of these very similar materials in both crystal and electronic structure show unexpected differences. All Raman features of WS2 monolayers are enhanced by the firstoptical excitations, but the response is not symmetric for the spin-orbit related XA and XB excitons. More interestingly, first order Raman bands of WSe2 are not enhanced at XA/B energies, but they are at the XC excitation. In this work, such intriguing phenomena are investigated by DFT calculations including excitonic effects by solving Bethe-Salpeter equation. We show that the ratio of the interaction of the XC to the XA excitons with the different phonons explains the different Raman responses of WS2 and WSe2 and the relative low Raman enhancement for the WSe2 modes at XA/B energies (see the figure). These results reveal unusual exciton-phonon interactions and open new avenues for understanding the physics of 2D materials, where weak screening plays a key role coupling different degrees of freedom (spin, optic, electronic).

References [1] [2]

E. del Corro, et. al. (submitted).

Yilei Li, et al., Phys. Rev. B. 90 (2014) 205422.

Figures

Figure 1: Comparison between the Raman excitation profile (REP) and the reflectance (adapted from [2] ) for WS2 and WSe2, showing qualitative differences

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Metrology for Graphene and 2-D Materials: Characterisation and Standardisation for an Emerging Industry Barry Brennan and Andrew J. Pollard National Physical Laboratory, Teddington, TW11 0LW, United Kingdom barry.brennan@npl.co.uk

Graphene has already demonstrated that it can be used to the benefit of metrology as a new quantum standard for resistance [1]. However, there are many application areas where graphene and other 2-D materials may be disruptive; areas such as flexible electronics, nanocomposites, sensing, filtration membranes and energy storage [2]. Applying metrology to the area of graphene is now paramount to enable the emerging global graphene industry and bridge the gap between academia and industry. Measurement capabilities and expertise for a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical and electrical properties, will allow the real-world issues of commercialising graphene and other 2-D materials, such as determining the suitability and realistic performance enhancement of graphene-enabled products for the many different types of graphene, to be addressed.

Examples of metrology challenges that have been overcome through cross-disciplinary research, newly developed measurement techniques and collaboration with both academia and industry will be discussed, for specific consumer application areas, using both established and emerging measurement techniques such as Raman spectroscopy, tipenhanced Raman spectroscopy (TERS) and secondary ion mass spectrometry (SIMS).

We will discuss the quantitative determination of the lattice disorder present in graphene layers through studying the evolution of Raman spectra with defect size and density, for vacancy defects created via carefully controlled ion bombardment, and explore how this enables an accurate determination of the phase-breaking length of graphene. This is further extended to other 2-D materials such as MoS2 and we investigate the application of Raman spectroscopy for quantification of defects in these systems.

We will further discuss understanding the measurement of real-world graphene samples, and the application of routine industry ready techniques, such as controlled mass-selected argon cluster cleaning to remove polymer residues present on the transferred graphene surface, which minimise damage to the underlying graphene. The application of SIMS measurements in these studies will be discussed, and further details of how it can be applied to the understanding of the growth mechanisms of graphene and other 2-D materials on metal catalysts will be explored. Other more novel applications of SIMS in relation to the characterisation of dispersed graphene materials in polymer composites for flexible device technologies, and how it can aid in identifying contamination and the degree of dispersion of different graphene products will also be presented. In addition, how these metrology

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investigations ultimately lead to the development of international graphene standards will also be described.

References [1] [2]

52

T.J.B.M. Janssen et al. Rep. Prog. Phys. 76 (2013) 104501.

K.S. Novoselov et al. Nature, 490 (2012) 192.

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Ultra high photoresponsivity with field effect control in a graphene nanoribbon device Andrea Candini1*, Leonardo Martini1,2, Zongping Chen3, Neeraj Mishra4, Camilla Coletti4, Akimitsu Narita3, Xinliang Feng5, Klaus MĂźllen3, Marco Affronte2,1 1Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A , 41125 Modena, Italy 2Dip. FIM, UniversitĂ di Modena e Reggio Emilia via G. Campi 213/A, 41125/A Modena, Italy 3Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany 4Center for Nanotechnology Innovation @ NEST, IIT, Piazza San Silvestro 12, 56127 Pisa, Italy 5CfAED & Dep. of Chemistry and Food Chemistry, TU Dresden, 01062 Dresden, Germany *andrea.candini@nano.cnr.it

We report on the realization and characterization of a novel concept of highly-performing nano-optoelectronic device, fully based on graphene. The active channel consists in a film of structurally well-defined graphene nanoribbons (GNRs) contacted by multilayer graphene electrodes. GNRs are grown by a large throughput chemical vapor deposition (CVD) method and are transferred on on pre-fabricated graphene electrodes.

The resulting device (see Figure 1) shows n-type field effect transistor (FET) behavior, with a large tunability of the device current with the applied gate voltage, likely as a consequence of the good affinity between the GNRs and the graphene-based electrodes, limiting the contact resistance. We demonstrate a current on/off ratio as high as 104 at room temperature, which is the best value reported so far for devices based on bottom-up fabricated GNRs. Our fully graphene-based devices show an ultra-high photo-responsivity at the visible-UV frequencies, as high as 106 A/W for low illumination powers, which is almost nine orders of magnitude higher than standard graphene. The improved sensitivity is ascribed to the semiconducting nature of the GNRs (with a direct bandgap of around 1.8 eV) and to the peculiar geometry of our device, where the contacts regions (i.e. the interface between the GNRs and graphene) is directly exposed to the light.

With the possibility to precisely tailor the chemical and physical properties of the GNRs directly at the synthetic level, and the demonstrated use of large scale production techniques, our results show the great potentialities of hetero-structured graphene devices for applications in nano-optoelectronics and sensing.

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Figures

Figure 1: Schematic view of the device: graphene nanoribbon (GNRs) are contacted using multilayer graphene as the electrode material.

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Fast One-Pot Synthesis of MoS2/Crumpled Graphene p-n Nanonjunctions for Enhanced Photoelectrochemical Hydrogen Production Francesco Carraro1, Laura Calvillo1, Mattia Cattelan1, Marco Favaro1,2, Marcello Righetto1, Silvia Nappini3, Igor Píš3,4, Verónica Celorrio5, David J. Fermín5, Alex Martucci6,Stefano Agnoli*,1 and Gaetano Granozzi1 1Department of Chemical Sciences, University of Padova, via Marzolo 1, Padua 35131, Italy 2Advanced Light Source (ALS) Joint Center for Artificial Photosynthesis (JCAP), Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., M/S 6R2100 Berkeley, CA 94720, USA 3 Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park-Basovizza, Strada Statale 14, Km.163.5, I-34149 Trieste, Italy 4 Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, Km.163.5, I-34149 Trieste, Italy 5School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, U.K. 6Industrial Engineering Department and INSTM, University of Padova, Padova 35131, Italy francesco.carraro.7@studenti.unipd.it

Besides being a material with exceptional electrical conductivity, outstanding mechanical toughness and remarkable optical properties, graphene is, at its very nature, a perfect and soft 2D atomic sheet. This combination of confinement to nanodimension and easy mechanical pliability makes it an incredibly versatile material that can be shaped in almost any form. This great potential for manipulation paves the way toward the development of advanced architectures that combine graphene intrinsic properties with nanodesign optimized for specific functions. [1] Interestingly, the two-dimensional nature of graphene implies the ability to undergo easy folding and bending, just like macroscopic objects, thus graphene sheets can be opportunely crushed to form crumpled nanoballs [2,3]. This special conformation is quite intriguing since it prevents the re-stacking of single sheets, allowing the preparation of high surface area systems Moreover, mechanical strain induced in the material by wrinkles and folds can promote unexpected chemical reactivity and better electrochemical performances. [4,5] Aerosol processing allows preparing in high yield and short time hierarchical graphene nanocomposites with special crumpled morphology, employing aqueous suspensions of graphene oxide(GO)[3]. By modular insertion of suitable precursors in the starting solution, it is possible to synthesize different types of graphene based materials ranging from heteroatoms doped graphene nanoballs, to hierarchical nanohybrids made up by nitrogen doped crumpled graphene nanosacks that wrap finely dispersed MoS2 nanoparticles. These materials are carefully investigated by microscopic (SEM, standard and HR TEM), grazing incidence X-ray diffraction (GIXRD) and spectroscopic (high resolution photoemission, Raman and UV-visible spectroscopy) techniques, evidencing that nitrogen dopants provide anchoring sites for MoS2 nanoparticles, whereas crumpling of graphene sheets drastically limits aggregation. The activity of these materials is tested toward the photo-electrochemical production of hydrogen, obtaining that N-doped graphene/MoS2 nanohybrids are seven times more efficient with respect to single MoS2 because of the formation of local p-n MoS2/N-doped graphene nanojunctions, which allow an efficient charge carrier separation.

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References [1] [2] [3] [4] [5]

Agnoli, S. and Granozzi, G. Surf. Sci. 2013, 609, 1-5.

Ma, X.; Zachariah, M.R. and Zangmeister, C.D. Nano Lett. 2011, 12, 486-489.

Mao, S.; Lu, G. and Chen, J. Nanoscale 2015, 7, 6924-6943.

Bissett, M.; Konabe, S.; Okada, S.; Tsuji, M. and Ago, H. ACS Nano 2013, 7, 10335-10343.

Wen, Z.; Wang, X.; Mao, S.; Bo, Z.; Kim, H.; Cui, S.; Lu, G.; Feng, X. and Chen, J. Adv. Mater. 2012, 24, 5610-5616.

Figures

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2D Materials: science and technology Antonio H. Castro Neto National University of Singapore. Singapore phycastr@nus.edu.sg

Over the last five years the physics of two-dimensional (2D) materials and heterostructures based on such crystals has been developing extremely fast. From one hand, with new 2D materials, more and more truly 2D physics started to appear (Kosterlitz-Thouless (KT) behaviour, 2D excitons, commensurate-incommensurate transition, etc). From another - we see the appearance of novel heterostructure devices - tunnelling transistors, resonant tunnelling diodes, light emitting diodes, etc. Composed from individual 2D crystals, such devices utilise the unique properties of those crystals to create functionalities which were not accessible to us in other heterostructures. In this talk I will review the properties of novel 2D crystals and how those properties are used in new heterostructure devices.

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Foldable Conductive Cellulose Fiber Networks Modified by Graphene Nanoplatelet-Bio-Based Composites Pietro Cataldi1, Ilker Bayer1, Athanassia Athanassiou1, Francesco Bonaccorso2, Vittorio Pellegrini2, Roberto Cingolani1,2 1Smart Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy 2Graphene Laboratories, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy pietro.cataldi@iit.it

Truly foldable electronic components require a stretchable/foldable substrate modified with a conducting element that can maintain its electrical properties and mechanical integrity even after severe mechanical manipulations and repeated folding events [1,2].

We design and realize a material with these characteristics, exploiting the combination of biodegradable components (substrate and the polymer matrix) and graphene nanoplatelets [3]. A commercially available thermoplastic starch-polycaprolactone based polymer (Mater-Bi) and graphene nanoplatelets are simultaneously dispersed in an organic solvent obtaining conductive inks [3]. The obtained inks are spray painted on pure cellulose papers and hot-pressed into their fiber network after drying. Transmission electron microscopy shows that during hot-pressing, the conductive ink is physically embedded into the cellulose fibers (see Figures a-b), resulting in high electrical conductivity of the flexible composite. The resultant nanostructure is a flexible composite which exhibits isotropic electrical conductivity, reaching a sheet resistance value in the order of ≈10 Ί/â–Ą, depending on the relative concentration of the graphene nanoplatelets and the Mater-bi.

Examples of excellent electrical conductivity are reported in Figures c-g. In Figure c, a photograph of a chip carrying 14 LED lights in contact with the conductor is presented. The circuit is powered by a 5V USB cable and the LEDs are lit up as shown in Figure c-d. The paper-like flexible conductors can sustain many harsh folding events (see Figure e-g), maintaining their mechanical and electrical properties and showing only a slight decrease of the electrical conductivity with respect to the unfolded sample. Unlike conductive paper technologies, the proposed paper-like flexible conductors demonstrate both sides electrical conductivity due to pressure-induced impregnation.

References [1] [2] [3]

58

W. J. Hyun et al., Adv. Mater. 34(2013), 4729-4734.

Z. Ling et al., PNAS, 47 (2014), 16676-16681.

Cataldi et al., Adv. El. Mater., 12(2015).

April 19-22, 2016 Genoa (Italy)

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Figures

Figure 1: (a) and (b) show cross-sectional TEM images of the conductive composite. (a) is a lower magnification. In (b) a higher magnification image shows many GnPs flakes embedded into the cellulose fibers. (c) and (d) are photograph of a LED chip placed on the foldable conductor. (c) shows a 14 LED chip lighting up once the foldable paper-like conductor is connected to a 5 V USB port of a computer. In (d) the same photograph of (c) was taken in dark. (e) is a photograph of a similar concept of (c) for a single LED attached to a conducting base with conducting paths embedded into the cellulose sheet. (f) represents the same material squashed and pressed into a wrinkled ball by hands. (g) exhibits a photograph of the paper-like conductor after unflattening the squashed ball of (f). The LED light still works after this severe mechanical treatment.

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April 19-22, 2016 Genoa (Italy)

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DNA Detection Using Graphene Field-Effect Transistors Jiri Cervenka Department of Thin Films and Nanostructures, Institute of Physics ASCR, v. v. i., Cukrovarnicka 10/112, 162 00 Prague, Czech Republic cervenka@fzu.cz

DNA is a nucleic acid molecule encoding genetic information, which has a vital role for the development and functioning of all known living organisms. Therefore, sensitive and selective detection of DNA is of fundamental importance for a large number of applications in medicine and biotechnology. Recent advances in graphene-based electrical sensors have demonstrated their unprecedented sensitivity to adsorbed molecules, which holds great promise for label-free DNA sequencing and detection.

Here we present a comparative study of the electronic detection of DNA on graphene fieldeffect transistors (GFETs) in vacuum and liquids. We compare the device sensitivity for direct detection of DNA on GFETs and using specific binding of target DNA with complementary DNA molecules attached to graphene, providing an estimate of the GFET sensitivity limit.

Furthermore, we analyze the ability of GFETs to directly discriminate individual DNA nucleobases in electronic transport measurements. We demonstrate that GFETs are able to measure distinct, coverage dependent, conductance signatures upon adsorption of DNA nucleobases in vacuum (Figure 1) [1]. This method allows for electronic discrimination of individual DNA nucleobases on GFETs, providing a first step towards graphene based electronic DNA sequencing. The existence of molecule specific signatures in electronic transport measurements is verified by independent synchrotron-based X-ray photoelectron spectroscopy (XPS) measurements. To get a deeper insight into the origin of the sensing mechanism and molecular recognition in GFET measurements we performed ab initio electronic structure calculations using density functional theory (DFT). The molecular recognition is found to be closely linked with specific noncovalent molecular interactions of DNA nucleobases with graphene. The absorption of molecules resulted in the electronic structure change of graphene which is driven by complex interplay between moleculegraphene and intermolecular interactions, interface dipole moment, charge transfer, work function change and screening effects. These effects open up a range of new opportunities for molecular recognition of different biomolecules in graphene-based electronic sensing.

References [1]

60

N. Dontschuk, A. Stacey, A. Tadich, K. J. Rietwyk, A. Schenk, M. T. Edmonds, O. Shimoni, C. I. Pakes, S. Prawer, and J. Cervenka, Nature Communications 6 (2015) 6563.

April 19-22, 2016 Genoa (Italy)

Graphene2016

Figures

Figure 1: a Detection of DNA nucleobases using GFETs, which is based on measurements of shifts of the Dirac point. b Coverage dependence of induced charge carrier density (determined from the Dirac point shifts) in GFETs by DNA nucleobases [1].

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April 19-22, 2016 Genoa (Italy)

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Graphene: Raw Graphite into Industrial Partnerships Gordon Chiu Grafoid Inc., Canada dr.chiu@grafoid.com

Grafoid’s journey into the industrial production of few layer Mesograf™ graphene from raw, graphite ore using a novel process has led to stunning results. Managing the alignment of human resources, investment capital and physical resources requires strategic planning, determination, R&D hubs and timing. Partnering with like-minded governments and persistent growth in industrial and academic partnerships have led to those collaborations that allow for the joint discovery of new applications and strong networks of support.

Today, our expansion continues with strong interest from academic, government, & industry partners seeking a de-risked multinational advanced materials company with an international presence and a robust infrastructure with multiple production sites. Grafoid is a diversified graphene company focused on cross-border production driven by application partnerships.

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Fabrication of Large Area Graphene Films and Their Applications Seungmin Cho, Kisoo Kim Hanwha Techwin, Seongnam-si, Gyeonggi-do, 13488, South Korea seungmin72@hanwha.com

Graphene, a single atomic layer of graphite, attracts enormous interest from academia and industry. Because of unique properties such as high mobility of charge carriers, ultra high young’s modulus and thermal conductivity, graphene is studied as candidate material for future applications in various fields such as electronics, optoelectronics, composite materials, and thermal management. Among many applications, transparent electrodes for (flexible) display are expected to be near term applications.

Chemical vapor deposition (CVD) has enabled the growth of single layer graphene on copper foil for arbitrary size. However, the practical use of graphene is hampered, since reliable and repeatable production of graphene film with uniform quality is limited. In this presentation, we report rapid thermal chemical vapor deposition (RT-CVD), improved etching and transfer methods, which enabled faster and larger production of homogeneous graphene films over 450 x 350 mm2 area. Resulting graphene films on PET have 90% total transmission (including PET) with sheet resistance ~200 Ί/sq. Further efforts are being made to fabricate ultra large size graphene film, which will be as large as 900 x 1600 mm2 . In collaboration with application experts, applications using graphene films are fabricated and tested. The effects of graphene films on the performances of applications will be briefly discussed.

References [1] [2]

J. Ryu, et al., ACS Nano, 8 (2014) 950.

S. Kim, et al., Chemistry of Materials, 26 (2014) 2332.

Figures

Figure 1: Processes and Equipment for Manufacturing Large Area Graphene.

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April 19-22, 2016 Genoa (Italy)

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Massless Dirac fermions in potassium-doped few-layer black phosphorus Hyoung Joon Choi Department of Physics, Yonsei University, Seoul, Korea h.j.choi@yonsei.ac.kr

Thin flakes of black phosphorus (BP) are a two-dimensional (2D) semiconductor whose energy gap is predicted being sensitive to the number of layers and external perturbations.

Very recently, it was found that a simple method of potassium (K) doping on the surface of BP closes its band gap completely, producing a Dirac semimetal state with a linear band dispersion in the armchair direction and a quadratic one in the zigzag direction [1]. Here, based on first-principles density functional calculations, we predict that beyond the critical K density of the gap closure, 2D massless Dirac fermions (i.e. Dirac cones) emerge in K-doped few-layer BP, with linear band dispersions in all momentum directions, and the electronic states around Dirac points have chiral pseudospins and Berry's phase [2]. These features are robust with respect to the spin-orbit interaction and may lead to graphene-like electronic transport properties with greater flexibility for potential device applications.

References [1] [2]

64

J. Kim, S. S. Baik, S. H. Ryu, Y. Sohn, S. Park, B.-G. Park, J. Denlinger, Y. Yi, H. J. Choi, and K. S. Kim, Science 349 (2015) 723.

S. S. Baik, K. S. Kim, Y. Yi, and H. J. Choi, Nano Letters 15 (2015) 7788.

April 19-22, 2016 Genoa (Italy)

Graphene2016

Ultrafast mid-infrared 1s intraexcitonic spectroscopy in monolayer MoS2 Soonyoung Cha1, Ji Ho Sung2,3, Sangwan Sim1, Hoseok Heo2,3, Moon-Ho Jo2,3, and Hyunyong Choi1,* 1School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 2Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea 3Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea *hychoi@yonsei.ac.kr

Ultrafast optical Photogenerated electron-hole pairs in solids create bound states whose elementary quasiparticle state is called 1s exciton in a Wannier-Mott exciton model. Above the fundamental 1s exciton, recent visible and near-infrared investigations revealed the excited excitons are much richer, exhibiting a series of Rydberg-like states [1,2]. Probing internal transition between these non-hydrogenic series, however, demand a fundamentally different experimental tool, capable of probing optical transitions from 1s “bright” to np “dark” states [3,4]. Here, we employed ultrafast mid-infrared spectroscopy to explore the 1sintraexcitonic transitions in monolayer MoS2 [5]. As shown in Fig. 1, we observed two-folded 1s→3p intraexcitonic transitions within A and B exciton and the 1s→2p transition between A and B exciton. Our time-resolved analysis revealed that it takes about 0.7 ps for the 1s A exciton before reaching quasi-equilibrium whose characteristic time is associated with a rapid population transfer from the 1s B exciton. Our experiment, otherwise hidden in linear or nonlinear spectroscopy, may provide a second look for understanding the many-body exciton dynamics in two-dimensional materials.

References [1] [2] [3] [4] [5]

D. Y. Qiu et al., Phys. Rev. Lett. 111 (2013) 216805.

A. Chernikov et al., Phys. Rev. Lett. 113 (2014) 076802.

R. A. Kaindl et al., Nature 423 (2003) 734-738.

C. Poellmann et al., Nat. Mater. 14 (2015) 899-893.

S. Cha et al., Nat. Comm. accepted for publication (2016).

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Figures

Figure 1: (a) Energy diagram of the excitonic Rydberg series in MoS 2. (b) transient band-to-band dynamics probed y 1.86 photon energy. (c-e) Transient dynamics of the intraexcitonic transition for each three oscillator are shown at each row: (c) 1s, A→3p,A, (d) 1s,B→3p,B, and (e) 1s,A→2p,B, respectively. Dashed lines show the maximum peak for each intraexcitonic transition.

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Graphene and 2D materials for future electronics and displays Sung-Yool Choi Graphene Research Center, School of Electrical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea sungyool.choi@kaist.ac.kr

Two-dimensional (2D) materials, including graphene, h-BN, transition metal dichalcogenides (TMDs), and so on, have huge potential to be exploited for the next-generation humanfriendly soft electronic and optoelectronic systems due to their unique electrical, optical, and mechanical properties. During past 5 years, the Graphene Research Center at KAIST (KAISTGRC), Korea, has demonstrated several electronic and optoelectronic devices based on low dimensional materials, i.e. field-effect transistors, gas sensors, nonvolatile memory devices, plasmonic waveguides, active metamaterials, and OLED displays, in which versatile properties of 2D materials have been incorporated into the electronic and optoelectronic platforms. However, there are several fundamental or technological issues to be addressed in the commercialization processes of 2D materials. In this talk, I will present the unique electrical characteristics of 2D materials and the recent advances in their synthesis and applications to electronics and displays fields at the KAIST-GRC.

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April 19-22, 2016 Genoa (Italy)

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Size-controlled functional graphene foams for applications in energy storage and piezoresistive sensing M. Christian1,2, L. Venturi2,3, L. Ortolani1 , R. Rizzoli1 , Z. Xia2 , V. Palermo2 , and V. Morandi1 1IMM, CNR, Bologna, Italy 2ISOF, CNR, Bologna, Italy 3University of Bologna Department of Physics, Bologna, Italy christian@bo.imm.cnr.it

3D graphene materials have attracted a lot of interest due to their ability to transfer many of the unique properties of 2D graphene to a larger scale, with high surface area, high electrical conductivity, and good structural integrity. Good quality graphene may be grown on templates of virtually any shape by Chemical Vapour Deposition (CVD), and in this way free-standing macrostructures called graphene foams (GF) were first produced from nickel foam templates in 2011 [1]. Since then there have been many investigations into their use either alone or in composites with other materials in applications such as electrodes for supercapacitors [2] and batteries [3], gas sensors [4] and adsorbents [5].

We present the promising preliminary results of two different applications that we are exploring for graphene foams. In the first, they are electrochemically functionalised with iron hydroxide, which is subsequently heated to produce flower-like iron (III) oxide nanocrystals completely covering the surface (Figure 1). The resulting composites show great potential for use in electrodes for Li-ion coin cell batteries. In the second application, graphene foams are coated with a thin layer of polyelastomer (PDMS) to improve their flexibility and strain recoverability, so that they can be used in piesoresistive pressure sensors for real-time monitoring of body signals.

In addition, we propose that the functional potential of graphene foams can be further improved by reducing the pore size from the 200-400 Âľm range typical of commercially available metal foam templates. We demonstrate a new technique to reach a pore size range of 1-10 Âľm using networks of nanoparticles as the templates for graphene growth, which significantly increases the graphene surface area available in a given volume (Figure 2).

References [1] [2] [3] [4] [5]

68

Z. Chen, W. Ren et al., Nat. Mater. 10 (2011) 424-428.

W. Deng et al., Mater. Lett. 137 (2014) 124-127.

Y. Tang et al., J. Power Sources 203 (2012) 130-134.

F. Yavari et al., Sci. Rep. 1 (2011) 166.

G. Chen et al., Appl. Surf. Sci. 311 (2014) 808-815.

April 19-22, 2016 Genoa (Italy)

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Figures

Figure 1: SEM images of functionalised graphene foams at increasing magnification, showing a) the porous structure and b) flower-like Fe2O3 nanocrystals on the surface.

Figure 2: a) SEM images of graphene foams from sintered Ni nanoparticle templates at increasing magnification and b) corresponding pore size distribution.

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Controlling the size of liquid exfoliated nanosheets and the impact of size on applications potential Jonathan N Coleman School of Physics and CRANN, Trinity College Dublin, D2, Ireland

In this talk, I will review liquid phase exfoliation as a method for producing 2D nanosheets, both of graphene and a range of other 2D materials including BN, transition metal dichalcogenides, metal oxides and hydroxides, III-VIs and black phosphorous. A new and efficient method to control nanosheets size, liquid cascade centrifugation (LCC), will be described. I will also discuss the use of spectroscopic metrics to measure mean nanosheet size, thickness and monolayer population in dispersion and show how this facilitates the production of dispersions with predetermined parameters such as high monolayer content.

Such systems are extremely useful in electrochemical applications such as supercapacitor and battery electrodes as well as hydrogen and oxygen evolution electrocatalysts. In such applications, nanosheet size tends to strongly impact performance. I will present both theoretical and experimental results showing the impact of nanosheet size on performance.

Finally, I will demonstrate that size-selected, liquid exfoliated nanosheets can be inkjetprinted to form functional heterostructures which can operate as photodetectors and supercapacitors.

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Towards a scalable synthesis of van der Waals heterostructures: from graphene on h-BN to WS2 on 2D substrates Neeraj Mishra1, Antonio Rossi1,2, Holger Buech1, Vaidotas Miseikis1, Carmine de Rienzo1,2, Domenica Convertino1,2, Ameer Al-Temimy1, Mauro Gemmi1, Vincenzo Piazza1, Camilla Coletti1 1 Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy 2Laboratorio NEST – Scuola Normale Superiore, and Istituto Nanoscienze – CNR, Piazza San Silvestro 12, 56127 Pisa, Italy

Two-dimensional (2D) heterostacks are typically obtained by mechanical exfoliation of 3D crystals and a cumbersome process of mechanical assembly. The limited lateral dimension of the resulting samples restricts the access to conventional techniques for fundamental studies and is a serious hurdle towards the implementation of a scalable technology. Chemical vapour deposition (CVD) is presently considered the most feasible approach towards a scalable synthesis of 2D heterostacks. In this talk, advances in the synthesis of van der Waals heterostructures will be presented. We have recently developed a catalyst-free process for the rapid synthesis of single-crystal graphene on h-BN with growth rates as high as 100 nm/min [1]. Our results indicate that hydrogen is the main driving force for engineering graphene crystallinity. Combined atomic force microscopy (AFM) and Raman spectroscopy show that circular grains obtained for low hydrogen partial pressures are polycrystalline. On the contrary, high hydrogen partial pressures yield single-crystal hexagonal-shaped graphene grains perfectly aligned to the h-BN substrate. Furthermore, we report on the scalable synthesis of the optoelectronically appealing WS2 on a variety of substrates. Notably, monolayer WS2 is obtained not only on classical 3D dielectrics but also on 2D films such as graphene and h-BN. Relevant properties of the synthesized heterostacks will be discussed.

References [1]

N. Mishra et al., Carbon 96, 497–502 (2016).

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Two-Dimensional Materials Growth Luigi Colombo Texas Instruments, USA colombo@ti.com

The isolation of graphene now over a decade ago has given rise to the revitalization of many twodimensional materials (2DM). The 2DM materials under investigation, in addition to graphene, include hBN, semiconducting, metallic, and superconducting 2DM. While h-BN is an excellent 2D insulator, TMD materials provide what graphene and h-BN cannot, a bandgap that can be used to create new heterostructure devices. A number of devices structures are currently under evaluation to take advantage of the properties of these materials. Some of the devices are based on tunneling which can be used to lower the voltage and power dissipation of a logic gate. In this presentation I will present a few grapheneand TMD-based devices processes required to make these devices a reality.

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Quantum effects in the nonlinear response of graphene plasmons Joel D. Cox1 and F. Javier García de Abajo1,2 1ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860 Barcelona, Spain 2ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain joel.cox@icfo.es

Graphene’s ability to support long-lived, electrically tunable plasmons that interact strongly with light [1], combined with its highly nonlinear optical response [2], has generated great expectations for application of the atomically-thin material to nanophotonic devices [3, 4].

Many of these expectations are reinforced by classical analyses performed using the response derived from extended graphene, neglecting finitesize and nonlocal effects that become important when the carbon layer is structured on the nanometer scale in actual device designs. Here we reveal strong finite-size and atomistic effects in the nonlinear response associated with plasmon resonances in graphene nanoribbons and nanoislands, predicted to take place from a realistic, quantum-mechanical (QM) description of these structures, beyond a semiclassical electromagnetic description, which produces dramatically different results for structure sizes up to several tens of nanometers. The discrepancy between classical and QM descriptions is particularly large for the complex third-order susceptibility associated with the Kerr effect and nonlinear absorption, where the classical theory underestimates the strength of the third-order response by several orders of magnitude even for ~40 nm structures. This is at odds with the conclusions previously drawn by examining the linear response regime, where classical and QM descriptions were found to agree well when either the plasmon energy is below the Fermi energy or when the sizes of the structure exceeds a few tens of nanometers. The QM effects reported here for such large sizes represent a rather unusual scenario in plasmonics, while they support the use of doped nanographene structures as plasmondriven nonlinear enhancers that perform much better than previously estimated from the study of extended graphene.

References [1] [2] [3] [4]

Z. Fang et al., ACS Nano, 7 (2013) 2388.

E. Hendry et al., Phys. Rev. Lett., 105 (2010) 097401.

A. N. Grigorenko, M. Polini, and K. S. Novoselov, Nat. Photon., 6 (2012) 749.

F. J. García de Abajo, ACS Photon., 1 (2014) 135.

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73

Figures

Figure 1: Linear and nonlinear spectral response of graphene nanoribbons. (a) We consider cw incident light linearly polarized across the ribbons (top) and present results derived from a quantummechanical (QM) model (tightbinding+random-phase approximation) for structures with either armchair or zigzag edges, compared with classical electromagnetic simulations (local conductivity) for a homogeneous planar sheet. (b-d) Linear absorption crosssection (b), and third-order susceptibilities for THG (c) and the Kerr nonlinearity (d), as obtained from the QM model for armchair (solid curves) and zigzag (dashed curves) nanoribbons, compared with classical electrodynamic simulations (filled curves). Different Fermi energies (color-coded numerical values in (b), eV) are considered, taking the ribbon width as ~10 nm and the damping ħτ-1 =50 meV in all cases.

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Spin dynamics, dephasing, and relaxation in clean and disordered graphene Aron W. Cummings1 and Stephan Roche1,2 1Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain 2ICREA, Instituci贸 Catalana de Recerca i Estudis Avan莽ats, 08070 Barcelona, Spain aron.cummings@icn.cat

Early on, graphene was expected to be an ideal material for spintronics applications, owing to its small spin-orbit coupling [1,2] and the subsequent prediction of long spin lifetimes [3,4].

Spin lifetime is an essential quantity that fixes the upper time and length scales on which spin devices can operate, so that knowing its value and variability is a prerequisite to realizing graphene spintronic technologies [5]. However, experimental measurements reveal spin lifetimes that are orders of magnitude lower than the original predictions [6,7]. A variety of extrinsic mechanisms have been proposed to explain this discrepancy, including enhanced SOC due to chemical adsorbates [8,9], or the presence of magnetic impurities [10].

Nevertheless, the exact nature of spin relaxation in graphene is still not entirely clear, and a deeper understanding of the spin relaxation mechanisms is needed.

In this work we use numerical simulations to examine the role of the substrate in determining the spin lifetime in graphene in the presence of Rashba SOC [11]. We consider both SiO2 and hBN substrates, and find that the spin relaxation mechanism is dictated by the substrateinduced electron-hole puddles. For the case of SiO2 we find that the spin lifetime follows a traditional Dyakonov-Perel behavior, while for hBN substrates the behavior is reminiscent of the Elliot-Yafet mechanism. This transition in behavior is determined by the ratio of the charge scattering time and the spin precession time induced by the Rashba SOC, and appears to echo recent experimental measurements [12].

Finally, we also consider the spin dynamics of graphene in the ultraclean limit [13]. Here the decay of the spin signal is driven by pure dephasing that arises from a combination of nonuniform spin precession and energy broadening. We show that reasonable values of Rashba SOC and energy broadening can lead to fast dephasing times, on the order of nanoseconds. This sets a fundamental upper limit on the spin lifetimes in ballistic graphene, indicating the need for careful control of the SOC and the energy broadening in this regime.

References [1] [2] [3] [4] [5] [6] [7]

H. Min et al., Phys. Rev. B, 74 (2006), 165310.

M. Gmitra et al., Phys. Rev. B, 80 (2009), 235431.

C. Ertler et al., Phys. Rev. B, 80 (2009), 041405.

Y. Zhou and M.W. Wu, Phys. Rev. B, 82 (2010), 085304.

S. Roche et al., 2D Materials, 2 (2015), 030202.

N. Tombros et al., Nature, 448 (2007), 571-574.

M.V. Kamalakar et al., Nat. Commun., 6 (2015), 6766.

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[8] [9] [10] [11] [12] [13]

76

A.H. Castro Neto and F. Guinea, Phys. Rev. Lett., 103 (2009), 026804.

D.V. Tuan et al., Nat. Phys., 10 (2014), 857-863.

D. Kochan et al., Phys. Rev. Lett., 112 (2014), 116602.

D.V. Tuan et al., Sci. Rep., 6 (2016), 21046.

M. Drรถgeler et al., Nano Lett., 14 (2014), 6050-6055.

A.W. Cummings and S. Roche, Phys. Rev. Lett., 116 (2016), 086602.

April 19-22, 2016 Genoa (Italy)

Graphene2016

Triangle-Shaped Graphene Domains by LP-CVD and Update of Graphene Application in Motive Power Battery Gui-Ping Dai1,2,3, K.Vinodgopal1 , Marvin H. Wu1 1Department of Chemistry, North Carolina Central University, Durham, NC 27707, USA 2Institute for Advanced Study, Nanchang University, Nanchang 330031, China 3Chaowei Power Ltd., Changxing 313100, China nanodai@gmail.com

The initial nucleation and growth dynamics of graphene play a critical role in determining the final quality of CVD graphene films, and it is highly desirable to synthesize large area high quality single crystalline graphene films [1, 2]. The shape and structure of individual graphene domains greatly influences its property and directly determines the grain boundary in polycrystalline graphene films. Thus, the tailoring and direct observation of the domain shape structure are very important for understanding the growth mechanism as well as to maximize single-crystalline graphene’s inherent outstanding properties for future applications. I will report the growth of large-scale “triangle� graphene domains on Cu foils during the early stage of CVD operated under low pressure. This work represents an important step toward realization of fabrication of larger area graphene sheets with controllable shape and alignment.

With the development of scientific and technological innovation over the past decades, graphene based products is growing rapidly around the world. Today lead-acid batteries are the most widely used rechargeable systems and still share about 65% of the rechargeable batteries market. Although leadacid systems were investigated and developed over 150 years, research continues to enhance their performance in terms of rate capability, stability, cycle life and durability [3]. Graphene is envisaged to enhance the performance of these batteries as the most efficient materials in terms of high intrinsic electrical conductivity, extremely lightweight, chemical inert, and flexible with a large surface area. The presence of graphene in the electrodes improves the electrical conductivity between the active mass particles through preventing thickening and the growth of large PbSO4 particles [4]. This improvement is naturally attributed to the formation of a stable conductive active mass matrix that enables the delivery and distribution of current to all the active material homogeneously. By enabling a uniform current distribution, and subsequently well distributed electrochemical redox reactions throughout the electrode matrix, arrested the formation of too large PbSO4 particles. The addition of graphene is supposed to improve both the mechanical stability and electrical integrity of the electrodes and to induce uniform changes in the active mass during the complicated conversion reactions during cycling. As the largest producer of motive power battery in the world, Chaowei has a potential need of graphene with 1000 tons/year. In this talk, I will present latest research of graphene commercially application in motive power battery, especially E-bike market.

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References [1] [2] [3] [4]

A. W. Robertson, J. H. Warner, Nano Lett., 2011, 11, 1182.

Guiping Dai, Marvin H. Wu, Darlene K. Taylor, K. Vinodgopal, Materials Research Letters, 2013, 1(2), 67-76.

Detchko Pavlov, Lead-acid batteries: science and technology (Book), Elsevier 2011.

Mo Shi, Guiping Dai, et al., Synthesis of Graphene and application in lead-acid battery, Chinese LABAT Man, 2015; 52(3): 142-145.

Figures

Figure 1: Typical SEM image of “triangle� graphene domains (Left) and cycle life of battery (Right).

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Origin of Improved Optical Quality of Monolayer Molybdenum Disulphide Grown on Hexagonal Boron Nitride Substrate Lun Dai, Yi Wan, Hui Zhang, Wei Wang, Bowen Sheng, Kun Zhang, Yilun Wang, Qingjun Song, Nannan Mao, Yanping Li, Xinqiang Wang, Jin Zhang State Key Lab for Mesoscopic Physics and School of Physics, Collaborative Innovation Center of Quantum Matter, Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China lundai@pku.edu.cn

We have devised and realized a high-yield and convenient method to synthesize monolayer MoS2 directly on h-BN flakes via the chemical vapor deposition (CVD) method.

Compared with that grown on SiO2/Si substrate, the monolayer MoS2 grown on h-BN exhibits enhanced photoluminescence (PL) and Raman signals as well as the smaller intensity ratio of E2g to A1g. Besides, its A1g Raman mode exhibits clear stiffening, whereas its E2g mode exhibits a negligible shift. We have calculated the PL intensity as function of both the h-BN thickness and the PL wavelength, based on light ray propagation in multilayer structure. Combining the theoretical and experimental analysis, we draw the conclusion that the enhanced PL and Raman signals of monolayer MoS2 originates probably from the relatively weak doping effect from the h-BN substrate, rather than the optical interference effect suggested previously. Using h-BN as substrate may provide a possibility of investigating the intrinsic property of mono layer MoS2, such as the novel valley-spin related property.

References [1]

Yi Wan, Hui Zhang, Wei Wang, Bowen Sheng, Kun Zhang, Yilun Wang, Qingjun Song, Nannan Mao, Yanping Li, Xinqiang Wang, Jin Zhang, and Lun Dai*, Small 12 , (2016) 198.

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Figures

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April 19-22, 2016 Genoa (Italy)

Graphene2016

Tunability of 1/f Noise at Multiple Dirac Cones in hBN Encapsulated Graphene Devices Chandan Kumar1, Manabendra Kuiri1, Jeil Jung2, Tanmoy Das1 and Anindya Das*,1 1Department of Physics, Indian Institute of Science, Bangalore 560012, India 2Department of Physics, University of Seoul, Seoul 130-742, Korea

The emergence of multiple Dirac cones in hexagonal boron nitride (hBN)−graphene heterostructures is particularly attractive because it offers potentially better landscape for higher and versatile transport properties than the primary Dirac cone. However, the transport coefficients of the cloned Dirac cones is yet not fully characterized and many open questions, including the evolution of charge dynamics and impurity scattering responsible for them, have remained unexplored. Noise measurements, having the potential to address these questions, have not been performed to date in dualgated hBN−graphene−hBN devices. Here, we present the lowfrequency 1/f noise measurements at multiple Dirac cones in hBN encapsulated single and bilayer graphene in dual-gated geometry. Our results reveal that the low-frequency noise in graphene can be tuned by more than two-orders of magnitude by changing carrier concentration as well as by modifying the band structure in bilayer graphene. We find that the noise is surprisingly suppressed at the cloned Dirac cone compared to the primary Dirac cone in single layer graphene device, while it is strongly enhanced for the bilayer graphene with band gap opening. The results are explained with the calculation of dielectric function using tightbinding model. Our results also indicate that the 1/f noise indeed follows the Hooge’s empirical formula in hBN-protected devices in dualgated geometry. We also present for the first time the noise data in bipolar regime of a graphene device.

Reference: Nano Letters, January 14, 2016

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April 19-22, 2016 Genoa (Italy)

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Exfoliation of Black-Phosphorus in low boiling point solvents and its application in Li-ion batteries Antonio Esau Del Rio Castillo1, Haiyan Sun1, Alberto Ansaldo1, Joka Buha2, Andrea Capasso1, Liberato Manna2, Vittorio Pellegrini1, and Francesco Bonaccorso1 1Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, Genoa, Italy 2Istituto Italiano di Tecnologia, Nanochemistry Department, Via Morego 30, Genoa, Italy antonio.delrio@iit.it

Black Phosphorus (BP) is a semiconductor layered material with a direct energy band gap [1]. The exfoliation of bulk BP to a few layers BP (FL-BP) flakes[2] allows the tuning of its (opto)electronic properties. Indeed, the energy band gap of BP changes from 0.33 eV to 1.7 eV when exfoliated from bulk to single layer[3,4]. This makes FL-BP an interesting material with potential applications in optics[5] and electronics[6,7]. Additionally, the layered structure and the chemistry of BP makes it also attractive for energy storage[8] and composite[9] applications. Recently, it was demonstrated the liquid phase exfoliation (LPE) of BP[9,10].

Unfortunately, this process is usually carried out in high boiling point (HBP) solvents[10,11], making the use of FL-BP very challenging in applications where both the toxicity and the removal of the solvent are a key, e.g., functional polymer composites[12] and printable inks[13,14].

Here, we show the LPE of BP in low boiling point (LBP) solvents, such as acetone (Fig. a), achieving material properties, i.e. lateral size (approx. 200 nm), thickness (~10 layers) and crystallinity (Fig. b), similar to the one exfoliated in HBP solvents. We used the FL-BP dispersed in acetone for the fabrication of lithium ion battery anodes. Our devices achieved a reversible specific capacity of 293 mAh g−1, see Fig. c, which is higher than those obtained by BP flakes exfoliated both in high boiling point solvents (CHP, giving a specific capacity of 55 mAh g-1), and water 180 mAh g-1 [8] (all tested at a current density of 100 mA g-1). Our approach represents a step further towards the fabrication of device components based on FL-BP.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

82

F. Xia, et al. Nature Communications, 5 (2014) 4458.

H. Liu, et al. ACS Nano, 8 (2014) 4033.

V. Tran, et al. Physical Review B, 89 (2014) 235319.

S. Das, et al. Nano Letters, 14 (2014) 5733.

M. Buscema, et al. Nature Communications, 5 (2014) 4651.

L. Li, et al,.Nature Nanotechnology, 9 (2014) 372.

Y. Deng, et al. ACS Nano, 8 (2014) 8292.

L. Chen, et al. Advanced Materials, 3 (2016) 510.

D. Hanlon, et al. Nature Communications, 6 (2015) 8563.

P. Yasaei, et al. Advanced Materials, 27 (2015) 1887.

April 19-22, 2016 Genoa (Italy)

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[11] [12] [13] [14]

J. Kang, et al. ACS Nano, 9 (2015) 3596.

S. Stankovich, et al. Nature, 442 (2006) 282.

F. Torrisi, et al. ACS Nano, 6 (2012) 2992.

A. Capasso, A. E. Del Rio, et al. Solid State Communications, 224 (2015) 53.

Figures

Figure 1: a) Image of FL-BP dispersion in acetone at different concentrations. b) High resolution transmission electron microscopy image of FL-BP flake; Inset: Fourier transform of the image, confirming the crystalline structure of the flake. c) Specific capacity over charge/discharge galvanostatic cycles, at different current densities, for the anode based on FL-BP in acetone (red triangles) and the one based on FL-BP in CHP (blue diamonds), at current density of 100 mA g-1.

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Graphene oxide lateral dimensions can mediate different molecular response of human immune cells Marco Orecchioni 1, Dhifaf Jasim 2, Mario Pescatori 1,3, Davide Bedognetti 4, Alberto Bianco5, Kostas Kostarelos2 and Lucia Gemma Delogu1* 1 University of Sassari , 07100 Sassari, Italy 2 Nanomedicine Laboratory, Faculty of Medical & Human Sciences, University of Manchester, Manchester M13 9PT, UK 3 Heath-E-Solutions, Rotterdam, 3016 DL Netherlands 4 Research Branch, Sidra Medical & Research Centre, Doha, Qatar 5 CNRS, Institut de Biologie Moléculaire et Cellulaire, Laboratoire d'Immunologie et Chimie Thérapeutiques, 15 rue René Descartes, 67000 Strasbourg, France lgdelogu@uniss.it; luciagemmadelogu@yahoo.it

In the last few years, there has been enormous interest in graphene oxide (GO) for its wide variety of applications [1, 2]. However, for any medical application, the immune systemimpact of GO still remain to be fully understood [3]. Here we focused on the molecular effects of two GOs, different for lateral size dimensions, on human primary immune cell populations: peripheral blood mononuclear cells (PBMCs). GOs were fully characterized, then we performed a wide range of standard assays looking at cell viability, cell activation and multiple cytokines secretion. We characterized the molecular impact of GOs on 84 genes immune-response-related. Additionally, a whole genome analysis was conducted on T cells and monocytes as representative of the innate and adaptive immune responses. In Fig. 1 TEM and AFM characterization of GO-Small (140 nm) and GO-Large (4m). We did not detect any toxicity in GO PBMCs treated samples. The 84 gene expression analysis evidenced a clear dimension-dependent impact of GOs on cell activation (Fig. 2). In particular, GO-Small modulated 16 genes (Fold Regulation >4) compared to only 5 of GOLarge (in red in Fig.2 C). Action confirmed also by cytokine analysis (Fig. 2 D). Further evidences were given by microarray analysis on T and monocytes cell lines. GO-Small impact the immune cell activation, underlined by the over expression of many pathways such as leukocyte chemotaxis pathway (Fig.3), genes such as CXCL10 and its receptor CXCR3 (Fig 3, red box). These genes are commonly activated during acute inflammatory processes as those associated with immune-mediated tumor rejection and pathogen clearance [4].

Moreover, we found a strong action on cell metabolism with a down-regulation on energetic pathways such as oxidative-phosphorylation pathway in both cell types (data not shown).

Our work represents a comprehensive molecular-characterization of different sized GOs on immune cells giving crucial information for the chemical and physical design of graphene for biomedical applications i.e. as a new possible drug delivery systems and nanoimmunotherapy tools.

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References [1] [2] [3] [4]

Sechi G, Bedognetti D, Sgarrella F, Van Eperen L, Marincola FM, Bianco A, Delogu LG. Nanomed. (Lond) 9 (2014) 1475-86.

Goldberg MS Cell 161 (2015) 201-4.

Orecchioni M, Bedognetti D, Sgarrella F, Marincola FM, Bianco A, Delogu LG, Journal of translational medicine 21; (2014) 12:138.

Pescatori M, Bedognetti D, Venturelli E, Menard- Moyon C, Bernardini C, Muresu E, Piana A, Maida G, Manetti R, Sgarrella F, Bianco A, Delogu LG. Biomaterials 34 (2013) 4395-403.

Figures

Figure 1: Characterizations of GO-Small and GO-Large. Atomic force microscopy (AFM) and transmission elettronic microscopy (TEM ) images of GO-Small and GO-Large respectively. All scale bars are 1µm.

Figure 2: Immune gene expression array. A) Heatmap comparison of 84 genes after exposure to GO-Small or GO-Large. B) Heat map detail showing the immune transcript upregulated by GOSmall in PBMCs. C) Table of modulate genes in GO-Small and GO-Large versus control. Red show genes with a fold change greater than 4, green show genes with a fold regulation less than 4. D) Multiplex cytokine secretion analysis of GO-small and GO-large samples, Interleukin 1β (IL1β), Tumor Necrosis factor α (TNFα) and Interleukin 10 (IL10) are showed.

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Figure 3: Whole genome expression analysis. Heatmap representation of GO-Small treatment for relevant Gene Ontology categories.

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Graphene-supported Fe, Co, Ni carbon nitride electrocatalysts for the ORR in alkaline environment Vito Di Noto1,2, E. Negro3,4, A. Bach Delpeuch1 , K Vezzù1 , F. Bertasi1 , G. Nawn1 , G. Pace2 , A. Ansaldo5 , M. Prato6 , M. Colombo6 , V. Pellegrini5 , F. Bonaccorso5 1Dep. of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy 2 CNR-IENI, Via Marzolo 1, 35131 Padova, Italy 3Dep. of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy 4Centro Studi di economia e tecnica dell'energia “Giorgio Levi Cases”, Via Marzolo 9, 35131 Padova, Italy 5Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, 16163 Genova, Italy 6Istituto Italiano di Tecnologia, Chemistry Department, Via Morego 30, 16163 Genova, Italy vito.dinoto@unipd.it

The development of advanced energy conversion systems characterized by a high efficiency and a low environmental impact is one of the most relevant targets of modern research [1]. As of today, important research efforts are devoted to low-temperature fuel cells (FCs) mounting an acid electrolyte, typically a proton-conducting membrane (e.g., Nafion®). To achieve a performance level compatible with current applications, these systems must adopt electrocatalysts (ECs) with a significant loading of platinumgroup metals (PGMs). In conventional low-temperature FCs, most of the PGM loading is typically concentrated at the FC cathode to promote the poor kinetics of the oxygen reduction reaction (ORR), one of the major bottlenecks in FC operation.

Very recently, viable OH- -conducting membranes were developed [2], opening the possibility to devise efficient anion-exchange membrane fuel cells (AEMFCs). In these systems the ORR takes place in an alkaline environment; accordingly, AEMFCs can adopt “Pt-free” ORR ECs and still achieve a high performance level. In this work, new “Pt-free” ORR ECs are reported; the materials comprise a graphene support “core”, which is covered by a carbon nitride “shell” coordinating the ORR active sites [3]. The proposed materials reap the benefits offered by graphene, including: (i) a high electrical conductivity, minimizing the ohmic losses; and (ii) a low microporosity, to facilitate the mass transport of reactants and products. The carbon nitride “shell” coordinates the bimetallic active sites, which include: (i) a 3d-“active metal” (i.e., Fe, Co, Ni), which bestows most of the ORR performance; and (ii) an oxophilic “co-catalyst” (Sn), which stabilizes the “active metal” and improves the ORR kinetics with a bifunctional mechanism.

The chemical composition of the ECs is determined by inductively-coupled plasma atomic emission spectroscopy (ICP-AES) and microanalysis; the thermal stability is studied by highresolution thermogravimetry (HR-TG); the surface chemical composition is explicated by Xray photoelectron spectroscopy (XPS); the morphology is elucidated in detail by highresolution scanning electron microscopy (HR-SEM) and high-resolution transmission electron microscopy (HR-TEM); the porosity is inspected by nitrogen physisorption techniques; the structure is investigated by wide-angle X-ray diffraction (WAXD), electron diffraction and

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micro-Raman; finally, the ORR performance and mechanism are clarified by means of cyclic voltammetry with the thin-film rotating ring-disk electrode (CV-TF-RRDE) method. The results proved very promising, clearly showing the potential of this family of “Pt-free”, “core-shell” graphene-supported ECs for application at the cathode of AEMFCs. In particular, CV-TFRRDE measurements in an alkaline environment demonstrated that the best material exhibits an ORR overpotential ca.70 mV higher with respect to a 10 wt.% Pt/C reference.

References [1] [2] [3]

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F. Bonaccorso, L. Colombo, G. Yu, M. Stoller, V. Tozzini, A. C. Ferrari, R. S. Ruoff, V. Pellegrini, Science, 347 (2015) 1246501.

G. A. Giffin, S. Lavina, G. Pace, V. Di Noto, J. Phys. Chem. C, 116, (2012) 23965.

V. Di Noto, E. Negro, K. Vezzù, F. Bertasi, G. Nawn, The Electrochemical Society Interface, Summer 2015, (2015) 63.

April 19-22, 2016 Genoa (Italy)

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Transport gap in vertical devices consisting of twisted graphene bilayers Philippe Dollfus1, Viet-Hung Nguyen1,2, Huy-Viet Nguyen2, Jérôme Saint-Martin2 1Institut. d'Electronique Fondamentale, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay, Orsay, France 2Center for Computational Physics, Institute of Physics, VAST, Hanoi, Vietnam philippe.dollfus@u-psud.fr

Controlling the misorientation of graphene layers has been experimentally explored and used to achieve resonant tunneling in vertical devices based on graphene/hexagonal boron-nitride/graphene heterostructures [1]. The commensurate-incommensurate transition in graphene on top of hexagonal boron-nitride has been also reported in [2]. We have previously investigated theoretically devices made of commensurate vertical stack of misoriented (twisted) graphene layers [3]. Here, by means of atomistic tight-binding calculations, we additionally investigate the transport properties of vertical devices made of an incommensurate graphene bilayer stack, where the two layers partially overlap, as illustrated in Fig. 1. For a given transport direction (Ox-axis), we define two classes of rotated graphene lattice distinguished by differences in lattice symmetry and, hence, in Brillouin zone, i.e., the two Dirac cones are located either at the same ky-point (K´yKy0) or at different ky-points (K´y Ky 2/3Ly), where Ly is the periodic length along the Oy axis). As a consequence, in devices made of two layers of different lattice classes, the misalignment of Dirac cones between the layers opens a finite energy gap of conductance that can reach a few hundreds of meV [4]. We also show that strain engineering can be used to further enlarge the transport gap in this type of device, as shown in Fig. 2 for different structures and different strain orientations. These results suggest an alternative strategy to open an energy gap in graphene channels, without altering the graphene lattices, by controlling the misorientation of graphene layers.

References [1] [2] [3] [4]

A. Mishchenko et al., Nat. Nanotechnol. 9 (2014) 808813.

C. R. Woods et al., Nat. Phys. 10 (2014) 451456.

V. Hung Nguyen, H. Viet Nguyen, J. Saint-Martin, and P Dollfus, Nanotechnol. 26 (2015) 115201.

V. Hung Nguyen, P. Dollfus, J. Phys. D: Appl. Phys. 49 (2016) 045306.

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Figures

Figure 1: Example of a device made of a vertical stack of misoriented graphene bilayer. The left layer has an amrchair orientation along the transport direction.

Figure 2: Strain effect on the transport gap in different devices. The angle ď ą is the strain of angle with respect to the transport direction Ox.

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The role of graphene in characterizing layered materials Mildred S. Dresselhaus Massachusetts Institute of Technology, 77 Massachusetts Ave, Bldg. 13-3005, Cambridge, MA 02139 USA

Starting with the general public consideration of graphite as a material too complex for detailed study 70 years ago, I will trace my experience with establishing for myself why graphite was worth studying, based on the conceptual promise of graphene. I also tried to study what were some of the special characteristics of graphite that might interest other people in sp2 carbon generally. I found graphene-related materials that were available to me to have interesting and unusual electronic properties that could be studied with techniques available to me. I was persuaded that the new resulting research directions suggested by sp2 carbons would be interesting, some examples being carbon fibers, clusters, nanotubes, and later nanoribbons. Studies of sp2 carbons brought our research group into new categories of layered materials in the early 1990s, like transition metal dichalcogenides in bulk form. After the Novoselov and Geim graphene paper in 2004, our research group also expanded our activities into nano forms of different types and for different layered materials.

Over the years, learning with and from my students and postdocs has expanded my research program and has advanced science and its application to society on an international basis

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Highly sensitive hexagonal boron nitride encapsulated graphene hot electron bolometers with a Johnson noise readout Dmitri K. Efetov, Yuanda Gao, Gabriele Grosso, Cheng Peng, Ren-Jye Shiue, Evan Walsh, Jim Hone, Kin Chung Fong and Dirk Englund MIT, USA

Graphene has remarkable opto-electronic and thermo-electric properties that make it an exciting functional material for various photo-detection applications. Its ultra broadband light absorption from the UV to the THz and a strong and ultra-fast photo-thermal-response allow to realize highly responsive photo-detectors with competitive sensitivities to state of the art detectors in the mid-IR and THz wave-lengths. In particular, owed to graphenes unique combination of an exceedingly low electronic heat capacity Ce and a strongly suppressed electron-phonon thermal conductivity Gth, the electronic and phononic temperatures are highly decoupled. These properties enable the use of graphene devices as ultra-sensitive hot electron bolometers (HEB) with predicted photo-detection sensitivities down to single terahertz photons.

Here we demonstrate highly sensitive HEBs made of high quality hexagonal boron nitride/graphene stacks (hBN/G/hBN) and employing a direct electronic temperature read out scheme via Johnson noise thermometry (JNT). The almost two orders of magnitude lower impurity concentrations of ﾏナ ~ 109 cm-2 in the hBN/G/hBN stacks, as compared to typical graphene devices on SiO2, translate into extremely low potential fluctuation of the Fermi energy ef ~ 5meV around the charge neutrality point. We perform combined mid-IR pumpprobe and JNT measurements to demonstrate the strongly damped Ce and Gth in this regime, which results in unprecedented photo-detection sensitivity and noise equivalent power for graphene HEBs. We can increase the sensitivity further, we demonstrate that we can integrate the hBN/G/hBN HEBs into photonic crystal cavities and silicon wave-guides, which enable an almost 20-fold enhancement of the light absorption. The ease and CMOS compatibility of the integration process of the HEBs onto silicon photonic circuits paves the way towards high-speed graphene-based photonic integrated circuitry.

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Multimodal Correlative Microscopy of 2D Materials Jan Englert, Thomas Dieing, and Ute Schmidt* WITec GmbH, Lise-Meitner Str. 6, Ulm, Germany (www.witec.de) Jan.Englert@witec.de

The characterization of 2D materials such as graphene or transition metal dichalogenides (TMDs) often require more than a single characterization technique to gather comprehensive information in order to understand and predict their behavior for specific applications. Graphene [1] and TMDs [2] have a layered structure in common, with significantly changes their properties when compared to in the bulk making them very attractive materials for electronic designs. The optimization of electronic device performance is strongly tied to the structure, degree of crystallinity and exciton dynamics of 2D materials. The scope of this contribution is to provide insight into how a combination of spectroscopic (Raman/Photoluminescence) and microscopy techniques (confocal/AFM/SEM) contribute to an ample characterization of such 2D materials.

Raman spectroscopy and more importantly still, Raman imaging proved to be of great value due to clearly different spectra obtained from single, double, triple and multi-layered 2D materials. Furthermore, Raman imaging is by now routinely used to determine strain, doping type and level, stacking, chirality and disorder in graphene. All these information can be extracted from Raman spectroscopy and imaging can well be complemented with other techniques such as various forms of atomic force microscopy (AFM), Scanning Nearfield Optical Microscopy (SNOM), Current sensing, scanning electron microscopy (SEM) or measurements at low temperatures (<10K) and under high magnetic fields (up to 9T).

The two dimensional forms of TMD materials are also often characterized using the same experimental methods. Fig. 1 shows an example of a correlative Raman-SEM measurement of CVD grown MoS2. For this group of 2D materials the information obtained through the combination of the techniques is even more valuable since the transition of indirect to direct semiconductor when going to a single layer gives rise to pronounced photoluminescence (PL)[3], which can easily be measured with exceptionally high resolution using SNOM-PL. In this contribution we illustrate the benefit of correlating the above mentioned techniques spatially applying confocal Raman imaging in order to deepen the understanding of the samples under investigation

References [1] [2] [3]

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, Science 306 (2004) 666 M. Xu, T. Liang, M. Shi and H. Chen, Chem. Rev. 113 (2013) 3766 A. Steinhoff, J.-H. Kim, F. Jahnke, M. Rรถsner, D.-S. Kim, C. Lee, G. H. Han, M. S. Jeong, T. O. Wehling and C. Gies, Nano Lett. 15 (2015) 6841.

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Figures

Figure 1: SEM-Raman imaging of CVD grown MoS2 on a Si-substrate: (a) SEM image, (b) Raman spectra evaluated from the 2D spectral array of a Raman image, and (c) RISE image, a combination of SEM and Raman image of the same sample area. The colors in the RISE image match the colors of the Raman spectra.

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ONYX Graphene and 2D Materials Inspector David Etayo1, Alex Lopez1, Magdalena Chudzik1, Montserrat Fernandez1, Luis E. Hueso2, Amaia Zurutuza3, Javier Tejada4, Eduardo Azanza1 1das-Nano, Polígono Industrial Mutilva Baja Calle G-6. E-31192 Mutilva Baja, Navarra. Spain 2CIC nanoGUNE. Tolosa Hiribidea, 76. E-20018 Donostia-San Sebastián, Spain 3Graphenea. Tolosa Hiribidea, 76. E-20018 Donostia-San Sebastián, Spain 4Dept. Fisica Fundamental, Universitat de Barcelona. C. de Martí i Franquès, 1,08028 Barcelona, Spain detayo@das-nano.es

Graphene production is increased every day, but current characterization techniques are only able to inspect it in nano-scale (confocal Raman Spectroscopy, TEM, AFM) or macro scale (optical microscopy, DC conductivity) [1]. Thus, das-Nano has developed a system based on THz technology, Onyx Graphene and 2D Material Inspector, which covers the gap between both techniques allowing the ultra-fast determination of the existence of inhomogeneities in the material. Onyx is able to characterize several materials such as CVD graphene (mono-, bi-, multilayer, flakes, doped), PEDOT; ITO, NbC, ALD samples or spin coated photoresins by a repeatable and reproducible measurement process.

Onyx is a THz-based system [2] for quality inspection of 2D materials which works in reflection configuration (as a difference with the state of the art methods [1-3]) and provides a conductance map of the full surface of the sample. The obtained results present a good correlation with current methods (Van der Pauw technique) [4].

Figure 1 shows the conductance maps of three samples. These sample were characterized using Raman Spectroscopy and optical microscopy. Based on this characterization, sample A and B were classified as good samples and sample C as bad sample. Onyx inspection results show that sample C is the bad one and sample B is the good one. The problem is sample A. The average conductance value is similar to sample B but its homogeneity is very different. Note that Onyx inspection takes less than 5 minutes while Raman inspection takes 3 days to obtain a comparable measure.

Onyx Graphene and 2D material inspector allows a very-fast (over 30 mm2,@ 1 mm2 resolution in less than a minute, spatial resolution of 100 µm) and non-destructive evaluation of the full surface of a 2D material sample. Furthermore, Onyx guaranties the repeatability and reproducibility of the results.

References [1] [2] [3]

J. D. Buron, et al, “Graphene Conductance Uniformity Mapping”, Nano Letters, Volume 12 Issue 10 (2012) pp 5074–5081.

N. Rouhi, et al, “Terahertz Graphene Optics”, Nano Research, Volume 5, Issue 10 (2012) pp 667-678.

F. Ellrich, et al, “Thin-Film Measurements with THz-Radiation”, 33rd International Conference on Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008.

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[4]

J. D. Buron,et al., â&#x20AC;&#x153;Electrically Continuous Graphene from Single Crystal Copper Verified by Terahertz Conductance Spectroscopy and Micro FourPoint Probeâ&#x20AC;?, Nano Letters, Volume 14, Issue 10 (2014) pp 6348-6355.

Figures

Figure 1: Conductance maps of several samples of CVD Monolayer Graphene at 0.5 THz.

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Graphene Standardization in IEC and ISO Norbert Fabricius1, Alexandra Fabricius2 1Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 EggensteinLeopoldshafen, Germany 2DKE – German Commission for Electrical, Electronic & Information Technologies of DIN and VDE, Frankfurt, Germany norbert.fabricius@kit.edu alexandra.fabricius@vde.com

One of the key success factors for the production of GRM-based products is the availability of material with a consistent quality as well as reliable fabrication processes. This requires that all stages in the fabrication process are controlled by sophisticated TQM methods with documented material specifications, test methods and standard operating procedures.

Furthermore, the manufacturer has to have a reliability assessment system in place to ensure that these products are reliable and safe. Establishing such processes is only possible with global standards that clearly define the key control characteristics and the related measurement methods. The Technical Committee 113 of the International Electrotechnical Commission has developed a consistent concept for graphene standardization which is also applicable to future standardization activities regarding other 2D materials.

This standardization process is a joint effort of IEC, ISO, CENELEC and IEEE and revolves around the central document, the standard IEC 62565-3-1. This so-called Blank Detail Specification (BDS) is a materials template that lists all relevant Key Control Characteristics (KCC) and will reference the standardized measurement protocols to measure them.

Currently, the working draft of IEC 62565-3-1 includes more than 30 KCCs including “number of layers”, “sheet conductance”, and “transmission”. While the first international standards on graphene are going to be published in 2016, the number of standardization projects in the responsible committee IEC/TC 113 is increasing rapidly. In this light it is evident that all standardization activities on national, regional and international level need to be coordinated to create a consistent standards system. As IEC 62565-3-1 provides a consensus list of KCCs, this document acts as a roadmap for graphene standardization. Furthermore, it is a template for other 2D materials that will be added to the system as additional parts of IEC 62565 series.

This talk will provide a review of the international standardization activities on graphene technologies and present the status reached within the IEC, IEEE and ISO nanotechnology committees and the recently established CENELEC Workshop on “Specifications for Graphene Related Materials (CENELEC WS SGRM)”. It will point out the importance to coordinate the worldwide standardization activities. IEC/TC 113 is the right place to do this.

All countries are invited to join the committee and submit their New Work Item Proposals to fill the gaps for the KCC measurement procedures and BDS standards for related 2D materials.

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Bright and dark excitons and trions in twodimensional metal dichalcogenides Vladimir Fal’ko National Graphene Ins., The University of Manchester, Booth St E, Manchester M13 9PL, UK

We analyse dark and bright states of charged and neutral excitons in two-dimensional transition metal dichalcogenides and metal-chalcogenide semiconductors.

In monolayer transition metal dichalcogenides (TMDC), where both conduction and valence band edges correspond to the Brillouin zone corner, optical spectra affected by the inverted sign of spin-orbit splitting of conduction band states in MoX2 and WX2. In WX2 ground state exciton is dark, whereas the ground state of exciton in MoSe2 is bright. Similarly, trions in MoSe2 are bright, whereas the ground state of the trion in WSe2 is only weakly radiative (semidark). Also, using diffusion Monte Carlo simulations, we developed interpolation formulae for the exciton and trion binding energies, taking into account the 2D lattice screening parameter, the electron/hole band masses, and electron-hole exchange.

In monolayer metal dichalcogenides InSe (stoichiometric In2Se2) and GaSe, band edges of conduction band and valence band appear near Г-point, and states have opposite symmetry with respect to z→-z mirror reflection, resulting in a weak coupling to the out-ofplane polarised photon. AB stacking of bilayer crystal of InSe (ABC-type for multilayers) violates mirror symmetry, making optical transition with the in-plane polarised light possible, however, only for the excited state of the exciton with angular momentum |Lz|=1. To this end, we study the dependence of the gap, effective mass and exciton binding energy on the number of layers. Also, the valence band appears to be quite interesting in all III-VI monolayers and few-layer films: it is almost flat over about 10% of the Brillouin zone area, with a weakly inverted dispersion at the Г-point, opening possibilities for strongly correlated states of holes in these materials.

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Towards Synthetic Two-Dimensional Soft Materials Xinliang Feng Center for Advancing Electronics Dresden & Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, Germany xinliang.feng@tu-dresden.de

Two-dimensional (2D) materials possess a structure with a topographical thickness generally ranging from atomic/molecular level to few hundreds of nanometers while the lateral dimensions are one or several orders of magnitude larger than the thickness; in addition, the aspect ratios in the planar dimensions are usually smaller than 10. As an important member filling in the gap among zero-dimensional, one-dimensional materials, and three-dimensional bulk materials, 2D materials have attracted great interest in both academic and industry.

Among them, 2D soft materials are flexible and show rich dynamics and self-assembly behavior determined by the subtle balance of energy and entropy. A typical example is graphene, a well-known 2D macromolecule, which is a single-layer graphite with closepacked conjugated hexagonal carbon lattices. Graphene possesses a large specific surface area along with exceptional electrical, mechanical, thermal and optical properties, and thereby shows great potential for applications in a variety of fields including energy conversion and storage, optoelectronics, catalysis, sensing, and biotechnology. In contrast to the extensive exploration of graphene and 2D inorganic materials such as metal dichalcogenides, metal oxides and nitrides, the study on 2D soft materials remains very limited.

In this lecture, we will present our recent efforts toward the chemical synthesis of novel 2D soft materials with structure control at the atomic/molecular-level or meso-scale. First, we will briefly demonstrate the latest efforts towards the synthesis of nanographenes and graphene nanoribbons with atomically precise structures. The synthesis strategy is based upon cyclodehydrogenation (“graphitization”) of well-defined dendritic (3D) polyphenylene precursors with different topologies, in solution or on surface. Second, we will address the synthetic 2D conjugated polymers including 2D metal-dithienene/diamine coordination polymers at air-water and liquid-liquid interfaces. The resulting 2D conjugated polymers exhibit single-layer feature, good local structural ordering and with a size of mm2. The first functional exploration of such 2D conjugated polymers for the efficient electrocatalytic water splitting will be demonstrated. Third, we will introduce the self-assembly of a host−guest enhanced donor−acceptor interaction, consisting of a tris(methoxynaphthyl)substituted truxene spacer, and a naphthalene diimide substituted with N-methyl viologenyl moieties as donor and acceptor monomers, respectively, in combination with cucurbit[8]uril as host monomer toward monolayers of an unprecedented 2D supramolecular polymers at liquid-liquid interface. Finally, we will present the synthesis of 2D conducting polymers, such as polypyrrole and polyaniline with adjustable mesopores on various functional free-standing surfaces, including 2D graphene, molybdenum sulfide and titania nanosheets. The unique structure with adjustable pore sizes (5–20 nm) and thickness (35–45 nm) as well as enlarged specific surface area provides excellent specific capacitance and rate performance for supercapacitors.

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The Roadmap to Applications of Graphene, Layered Materials and Hybrid Systems Andrea C. Ferrari Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 OFA, UK

3D graphene materials have attracted a lot of interest due to their ability to transfer many of Disruptive technologies are usually characterised by universal, versatile applications, which change many aspects of our life simultaneously, penetrating every corner of our existence. In order to become disruptive, a new technology needs to offer not incremental, but dramatic, orders of magnitude improvements. Moreover, the more universal the technology, the better chances it has for broad base success. The Graphene Flagship has brought together universities, research centres and companies from most European Countries. At the end of the ramp-up phase significant progress has been made in taking graphene, related layered materials and hybrid systems from a state of raw potential to a point where they can revolutionize multiple industries. I will overview the progress done thus far and the future roadmap.

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Towards all-electric spintronics in graphene Aires Ferreira Department of Physics, University of York, York YO10 5DD, United Kingdom aires.ferreira@york.ac.uk

Recent reports of sizeable spin–orbit coupling in chemically modified graphene have paved the way for all-electric spintronics in two-dimensional carbon platforms [1]. In this talk, I will overview the progress on spin Hall effect engineering in functionalized graphene [2-3], and discuss the implications of recent findings [4,5]. The main focus will be on spin– orbit coupled graphene obtained via chemisorption of light species and proximity effect to heavy adatoms. I will show theoretically how sharp electron—adatom scattering processes enable an efficient spin Hall current generation (spin Hall angles of the order of 10% [3]) with a low impact on spin relaxation times, making spin–orbit-coupled graphene a promising candidate for processing of neutral spin currents (see Fig. 1). Last, I will present a new proposal for spin-current routing based on the distortion of Dirac cones in graphenebased superlattices [5]. The implications for experiments will be briefly discussed.

References [1] [2] [3] [4] [5]

Marchenko, D. et al. Nat. Comm. 3, 1232 (2012); Balakrishnan, J. et al. Nat. Phys. 9, 284 (2013).

Balakrishnan, J. et al. Nat. Comm. 5, 4748 (2014); Avsar, M. et al. ibidem, 4875 (2014).

Ferreira, A. et al. Phys. Rev. Lett. 112, 066601 (2014); Pachoud, A. et al. Phys. Rev. B 90, 035444 (2014).

Stabile, A. et al. Phys. Rev. B 92, 121411(R) (2015).

Martelo, L., and Ferreira, A. (unpublished).

Figures

Figure 1: Direct and inverse Spin Hall effects in a graphene H-bar (Credit: J. Balakrishnan).

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April 19-22, 2016 Genoa (Italy)

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The Graphene Flagship Mikael FogelstrĂśm Microtechnology and Nanoscience MC2, Chalmers University of Technology, Sweden

Graphene, discovered and demonstrated as late as 2004 by A. Geim and K. Novoselov, has rapidly gone from fuelling curiosity driven condensed-matter research to being considered as a material for vast diversity of applications. Graphene has the potential to revolutionise knowledge-based industries in which ideas from fundamental sciences and university laboratories rapidly find their way into applied technologies.

The Graphene Flagship is tasked with bringing together academic and industrial researchers to take graphene from the realm of academic laboratories into European society in the space of 10 years, thus generating economic growth, new jobs and new opportunities. With a target budget of â&#x201A;Ź1 billion, the Graphene Flagship represent a new form of joint, coordinated research on an unprecedented scale, forming Europe's biggest ever research initiative. In my presentation I will give a current overview of the on-going work in and challenges met by the Graphene Flagship project.

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Mechanics of Suspended and Supported Graphene C. Galiotis Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece FORTH/ ICE-HT, GR-26504 Patras, Greece c.galiotis@iceht.forth.gr, galiotis@chemeng.upatras.gr

Graphene is an ideal 2D crystal which is believed to possess a unique combination of mechanical properties [1] in tension; that is high stiffness (~1 TPa), high strength (>100 GPa) but also high ductility (>20%) [2]. Theoretical works and simulations have indeed confirmed graphene as the stiffest and strongest material ever made but experiments on suspended graphene are scarce and problematic. A seminal work reported in [3] employing a radial tensile field by bending of graphene with an AFM probe, was converted by the authors to axial stress-strain curve by assuming almost zero bending stiffness and quadratic stress-strain relationship. By assuming a thickness of 0.335 nm (the interlayer spacing in graphite) similar values to those mentioned above were derived. However, as it was recently confirmed experimentally [4], when a suspended 1LG graphene is stretched axially then a very different situation is encountered as the suspended flake is expected to exhibit orthogonal (lateral) Euler buckling due to its small thickness. This behaviour is analogous to that observed for all thin membranes and even for biological materials stressed in one direction. Thus out-of-plane phenomena (Fig.1) cannot be ignored for certain modes of loading of suspended graphene.

For simply-supported or even fully-embedded graphene a number of experimental studies have been conducted. Normally, graphene flakes are subjected to a cyclic uniaxial deformation (tension and compression) using flexed beams (cantilever or 4-point). In tension, for both simply-supported and fullyembedded graphene the Raman 2D or G peaks are shifted with strain; the latter also shows splitting with strain due to the lifting of the degeneracy of the E2g mode [4,5]. Using this technique one can load graphene flakes up to ~1.5-1.7% of tensile strain. Judging from the perfect linearity of the 2D peak with strain it is assumed that the supported/ embedded graphenes behave linearly elastic up to that level of strain. In compression, the mechanical behaviour of several simply-supported or embedded monolayer graphene flakes with various length-to-width ratios have also been fully examined [6]. The critical strain to buckling for fully embedded graphene was found to be ~0.6% and independent of the flakeâ&#x20AC;&#x2122;s dimensions. This is indeed an extraordinary result for such a thin 2D crystal and its significance for engineering applications will be discussed.

Regarding lateral buckling under uniaxial tension in order to reach such a high value of buckling strain the corresponding axial tensile strain should be higher than ~2.0% (assuming a polymer Poissonâ&#x20AC;&#x2122;s ratio of ~0.35). Another option for effective graphene composites is the geometry of the embedded flakes; since a transfer length of about 2 Îźm is needed in order to have sufficient stress transfer from the surrounded polymer to the graphene [7] then any ribbons less than twice that value (

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References [1] [2] [3] [4] [5] [6] [7]

C. Galiotis et al., Ann. Rev. Chem. Biomol. Eng., 6, 121-140 (2015).

C. Lee et al., Science 321, 385 (2008).

Polyzos et al., Nanoscale 7, 13033 (2015).

G. Tsoukleri et al., Small 5, 2397 (2009).

O. Frank et al., ACS Nano 4, 3131 (2010).

C. Androulidakis et al., Sci. Rep. 4 5271 (2014).

Gong et al., Adv. Mat. 22, 2694 (2010).

Figures

Figure 1: (a) Raman intensity (I) and frequency (Ď&#x2030;) variation of the G and 2D sub-peaks in the transverse direction to strain axis. (b) Schematic of wrinkle (buckle) formation due to lateral compression and Raman map of the 2D peak intensity of graphene flake, I(Ď&#x2030; 2D).

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Construction of Novel 2D Atomic Crystals on Transition Metal Surfaces and Physical Properties: Graphene, Silicene, Germanene, Hafnene, PtSe2 and HfTen Hong-Jun Gao Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190, China hjgao@iphy.ac.cn

The novel properties of graphene-like honeycomb structure have spurred tremendous interest in investigating other two-dimensional (2D) layered structures beyond graphene. In this lecture, I will present construction of graphene, silicene, germanene, hafnium honeycomb lattice, monolayer PtSe2 as well as HfTe3/HfTe5, a superconductor-topological insulator layered heterostructure, on transition metal surfaces (TMS) (for example, Ru(0001), Pt(111), Hf(0001) and Ir(111)). Molecular beam epitaxial growth technique is used to form the large scale 2D atomic crystals on TMS. Low electron energy diffraction (LEED) and scanning tunneling microscopy/spectroscopy (STM/S) together with density functional theory (DFT) calculations are employed to confirm the formed structures on the TMS. In addition, we have successfully intercalated Si-layer at the interface between the formed graphene and the Ru(0001). The intercalation mechanism has been clarified with STM observations at an atomic level and the DFT calculations. We expect that these new 2D crystals materials will show very interesting physical property and its promising potential applications in nanoscale devices.

In collaboration with Y.L. Wang, S.X. Du, H.M. Guo, L. Huang, H.T. Yang, J.T. Sun, Y. Pan, L. Meng, L.F. Li, G. Li, Y.Q. Wang, X. Wu, L.Z. Zhang, S.R. Song, J.B. Pan et al. from Institute of Physics, CAS; Z.H. Qin from Wuhan Institute of Physics and Mathematics, CAS; S.Y. Zhou from Tsinghua University; S. Pantelides from Vanderbilt University, US; A. Ferrari from University of Cambridge, UK; M. Ouyang from Maryland University, US; W.A. Hofer from the University of Liverpool, F. Liu from University of Utah, US.

References [1] [2] [3] [4] [5] [6] [7]

Y. Pan et al., Adv. Mater. 21 (2009) 2777.

L. Meng et al., Nano Lett. 13 (2013) 685.

L.F. Li et al., Nano Lett. 13 (2013). 4671.

L.F. Li et al., Adv. Mater. 26 (2014) 4820.

Y.L. Wang et al., Nano Lett. 15 (2015) 4013.

G. Li et al., J. Am. Chem. Soc. 137 (2015) 7099.

Y.Q. Wang et al., Adv. Mater. DOI: 10.1002/adma.201600575 (2016).

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Graphene 2016-2026: Markets, Technologies and Players Khasha Ghaffarzadeh IDTechEx, Downing Park, Station Road, Cambridge, CB25 0NW, United Kingdom khasha@IDTechEx.com

The graphene industry is still largely in the red and company valuations are generally on the decline. Despite this, the industry is beginning to register revenue growth. Indeed, IDTechEx Research forecasts that revenues will reach $30m in 2016 with research and grant money continuing to play a substantial role. The market will not sustain all the suppliers and the conditions are ripe for consolidation since the landscape is populated with too many weaklycapitalized and poorly-differentiated players that each generate small revenues. This will benefit the industry as a whole since it will reduce the market fragmentation and creates larger and better consolidated entities able to stand on their own feet.

IDTechEx Research forecasts that the market will grow to $220m in 2026. This forecast is at the material level and does not count the value of graphene-enabled products. In many instances graphene is an additives with low wt% values. This revenue growth will be accompanied by a continued decline in average sales prices, meaning that volume sales will reach nearly 3.8 k tpa (tonnes per annum) in 2026. Our forecasts suggest that the industry will remain in a state of over-capacity until 2021 beyond which time new capacity will need to be installed. Furthermore, IDTechEx Research forecasts that nearly 90% of the market value will go to graphene platelets (vs. sheets) in 2026.

The market will be segmented across many applications, reflecting the diverse properties of graphene. In general, we expect functional inks and coatings to reach the market earlier.

This is a trend that we forecasted several years ago and is now observed in prototypes and small-volume applications. Ultimately, energy storage and composites will however grow to be the largest markets for graphene, controlling 25% and 40% of the market in 2026, respectively.

In this talk, IDTechEx Research will provide a critical review of the market, analyzing the latest trends and market movements. We will then quantitatively describe the business landscape as it exists today and will give our insight on how the industry will evolve over the coming decade. We will then focus on key areas of application focus in the industry such as inks and coatings, composites and various energy storage applications.

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Figures

Figure 1: Ten-year market projections split by application. Actual data will be shown in the conference. Inset: market share of graphene platelets vs sheets in 2026 by value. Source: IDTechEx

Figure 2: Left: accumulative investment in new graphene companies. This excludes money spent internally by large organisations on their own R&D. More than $200m has been invested. This figure is based on interviews, company visits, financial statements, press releases, etc. Right: expected revenue for graphene companies in 2026. This figure also includes some limited equipment sales.

Actual data will be shown in our presentation. Source: IDTechEx.

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When graphene meets perovskites Feliciano Giustino Department of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom feliciano.giustino@materials.ox.ac.uk

In recent years the energy conversion efficiency of solar cells based on halide perovskites skyrocketed above 20%, making these systems among the most promising solutionprocessable photovoltaics technology to date. At the same time graphene is the prime candidate for TCO replacement in optoelectronic devices. Given the exceptional and complementary properties of these two materials, it is expected that their combination into the same device may lead to significant improvements in solar energy technology and lightemitting devices. During the past three years in our group at Oxford we have been investigating photovoltaics materials based on graphene, perovskites, and their combinations using state-of-the-art atomic-scale first-principles calculations [1-7]. In the first part of the talk I will describe our work on graphene/perovskite composites [1]. Unexpectedly we found that even for ideal planar interfaces between graphene and perovskites, the interface chemistry induces an unusual ferroelectric distortion in the perovskite layer, which results from a slight octahedral tilt in the basal plane (Figure 1). Our calculations show that this interfacial ferroelectricity should carry the dual advantage of promoting charge extraction and inhibiting electron-hole recombination. If confirmed by experiments, this mechanism could not only be important in photovoltaics, but also provide new pathways for engineering ferroelectricity in other graphene/perovskite interfaces, for example in the context of solar water splitting. In the second part of the talk I will discuss our recent work in the area of computational modelling of graphene/polymer interfaces for organic solar cells, as well as high-throughput computational searches for Pb-free photovoltaic perovskites. In the former case we investigated the role of functional groups on the interfacial energy-level alignment and on the photovoltage [3]. In the latter case we performed a computational screening of all hypothetical halide perovskites with divalent metal cations, and identified Mg as a candidate for partial Pb replacement [7].

References [1] [2] [3] [4] [5] [6] [7]

G. Volonakis, F. Giustino, J. Phys. Chem. Lett., 6 (2015) 2496.

M. R. Filip, G. E. Eperon, H. J. Snaith, F. Giustino, Nat. Commun., 5 (2014) 5757.

K. Noori, D. Konios, M. Stylianakis, E. Kymakis, F. Giustino, 2D Mater., 3 (2016) 015003.

M. R. Filip, F. Giustino, Phys. Rev. B, 90 (2014) 245145.

M. R. Filip, C. Verdi, F. Giustino, J. Phys. Chem. C, 119 (2015) 25209.

M. A. Perez-Osorio, R. L. Milot, M. R. Filip, J. B. Patel, L. M. Herz, M. B. Johnston, F. Giustino, J. Phys. Chem. C, 119 (2015) 25703.

M. R. Filip, F. Giustino, J. Phys. Chem. C, 120 (2016) 166.

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Figures

Figure 1: Induced ferroelectricity at the interface between graphene and the halide perovskite MAPbI3.

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Two-Dimensional Carbides (MXenes): Synthesis, Properties and Applications Yury Gogotsi Department of Materials Science and Engineering, and A. J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA; nano.materials.drexel.edu

Two-dimensional (2D) solids – the thinnest materials available to us – offer unique properties and a potential path to device miniaturization. The most famous example is graphene, which is an atomically thin layer of carbon atoms bonded together in-plane with sp2 bonds. In 2011, an entirely new family of 2D solids – transition metal carbides (V2C, Ti3C2, Nb4C3, etc.) and nitrides – were discovered by Drexel University scientists [1]. Selective etching of the A-group element from a MAX phase results in formation of 2D Mn+1Xn solids, labeled “MXenes”. 17 different 2D carbides and carbonitrides have been reported to date [2-5]. A new sub-family of multi-element ordered MXenes was discovered recently [2]. Structure and properties of numerous MXenes have been predicted by the density functional theory, showing that MXenes can be metallic or semiconducting, depending on their composition, structure and surface termination. Their elastic constants along the basal plane are expected to be higher than that of the binary carbides. Oxygen or OH terminated MXenes, are hydrophilic, but electrically conductive (up to 6000 S/cm). Hydrazine, urea, amines and other polar organic molecules can intercalate MXenes leading to an increase of their c lattice parameter [3].

Colloidal solutions of single- and few-layer MXene flakes can be used to manufacture MXene films with controllable optical and electronic properties. One of the many potential applications for 2D Ti3C2 is in electrical energy storage devices such as batteries, Li-ion capacitors and supercapacitors [3-6]. Cations ranging from Na+ to Mg2+ and Al3+ intercalate MXenes. Ti3C2 paper electrodes, produced by vacuum assisted filtration of an aqueous dispersion of delaminated Ti3C2, show a higher capacity than graphite anodes and also can be charged/discharged at significantly higher rates. They also demonstrate very high intercalation capacitance (up to 1000 F/cm3) [5].

References [1] [2] [3] [4] [5] [6]

M. Naguib, et al, Advanced Materials, 23 (37), 4207-4331 (2011).

B. Anasori, et al, ACS Nano, 9 (10), 9507–9516 (2015).

O. Mashtalir, et al, Nature Communication, 4, 1716 (2013).

M. R. Lukatskaya, et al, Science, 341 (6153), 1502-1505 (2013).

M. Ghidiu, et al, Nature, 516, 78–81 (2014).

M. Naguib, Y. Gogotsi, Accounts of Chemical Research, 48 (1), 128-135 (2015).

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Controlling atomic scale magnetism on graphene using hydrogen atoms H. GonzĂĄlez-Herrero1, J. M. Gomez-Rodriguez1,2,3, P. Mallet4,5, M. Moaied1, J. J. Palacios1,3, C. Salgado1, M. M. Ugeda6,7, J.Y. Veuillen4,5, F. Yndurain1,3 and I. Brihuega1,2,3 1Dept. Fisica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid, Spain 2Insitututo Nicolas Cabrera, Universidad Autonoma de Madrid, E-28049 Madrid, Spain 3Condensed Matter Physics Center IFIMAC, Universidad Autonoma de Madrid, E-28049 Madrid, Spain 4 UniversitĂŠ Grenoble Alpes, Institut NEEL, F-38042 Grenoble, France 5CNRS, Institut NEEL, F-38042 Grenoble, France 6CIC nanoGUNE, 20018 Donostia-San Sebastian, Spain 7Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain josem.gomez@uam.es

Isolated hydrogen atoms adsorbed on graphene are predicted to induce magnetic moments. Direct observation of these magnetic moments and their interactions as well as their manipulation still remains a major experimental challenge. Here [1] we demonstrate that the adsorption of a single hydrogen atom on graphene induces a magnetic moment characterized by a 20 meV spin-split state at the Fermi energy. Our scanning tunneling microscopy (STM) experiments, complemented by first-principles calculations, show that such a spin-polarized state is essentially localized on the carbon sublattice complementary to the one where the H atom is chemisorbed. This atomically modulated spin-texture, which extends several nanometers away from the H atom, drives the direct coupling between the magnetic moments at unusually long distances. The magnetic nature of the H induced graphene state is confirmed by external electronic doping. Using the STM tip to manipulate H atoms with atomic precision, we demonstrate the possibility to tailor the magnetism of selected graphene regions

References [1]

H. Gonzalez-Herrero, J. M. Gomez-Rodriguez, P. Mallet, M. Moaied, J. J. Palacios, C. Salgado, M. M. Ugeda, J.Y. Veuillen, F. Yndurain and I. Brihuega, Science (in press).

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High performance graphene flexible and transparent sensor platform with application in health sensing Stijn Goossens, Eric Puma, Juan-Jose Piqueras, Marc Montagut, Tania Lasanta, Gabriele Navickaite, Turgut Durduran, Gerasimos Konstantatos, Frank Koppens ICFO â&#x20AC;&#x201C; The Institute of Photonic Sciences, Av. Carl Friedrich Gauss, 3, 08860 Castelldefels (Barcelona), Spain stijn.goossens@icfo.es

There is a large demand for sensors that can be easily integrated with many different objects.

The rising trend of the internet-of-things illustrates the need for electronic sensing by any object surrounding us. Especially in health care the promises of using ubiquitous sensors are very high. Remote health monitoring will minimize hospital visits for patients and give doctors early warnings in case of developing illnesses.

Sensors for ubiquitous sensing should be cheap, invisible and easy to integrate with many different surfaces such as bendable plastic, fabric and glass. Transparent, wide wavelength range and flexible are key properties for a sensor used in remote monitoring. Here we present a novel sensor platform with these properties.

The technology is based on graphene and colloidal quantum dots which gives the sensor not only a high signal to noise ratio, but also provides inherent flexibility and transparency [1]. By using PEN as a substrate for the graphene and quantum dots we made the entire system flexible and transparent (see figure 1a). Our hybrid photodetectors cover a much wider wavelength range than conventional silicon detectors: 400 â&#x20AC;&#x201C; 2000 nm. They have a very low noise equivalent irradiance of <10-6 W/m2 and time response is below 5 ms. The detector is stable in ambient conditions and even after 2000 bending cycles it does not lose performance.

As a proof of applicability we made a flexible and transparent heart rate sensor (see figure 1b). The heart rate sensor measures reflected light from the skin that is modulated by the blood pulse. The sensor works in many different real world lighting conditions. This application demonstrates not only the robustness of the technology, but also the high dynamic range.

Future developments of the sensor platform will exploit the broad wavelength range. Both ends of the spectrum will enable new health monitoring devices that can be integrated on a simple invisible patch on the skin.

References [1]

] G. Konstantatos, M. Badioli, L. Gaudreau, J. Osmond, M. Bernechea, F. P. Garcia de Arquer, F. Gatti and F. H. L. Koppens, Nature Nanotechnol., 7 (June 2012). Hybrid graphene-quantum dot detectors with ultrahigh gain.

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Figures

Figure 1: (a) Wrist band with graphene sensor. (B) A working prototype system in the form of a wristband, including a tablet to display the pulse in real time.

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Graphene, an incredible innovation opportunity for a fast transformation of the energy industry Louis Gorintin , Laurent Baraton, Frederique Lebovits CRIGEN Nanotech Energy, Research & Technology Division, ENGIE. 361, av. Pdt Wilson, BP 33, 93211 Saint Denis La Plaine Cedex, France louis.gorintin@engie.com

As a major energy player ENGIE develops its businesses (power, natural energy and energy services) around a model based on responsible growth to take up today’s major energy and environmental challenges: meeting energy needs, ensuring the security of supply, fighting against climate change and maximizing the use of resources.

Innovation is a key assets to achieve this development and as one of the most active domain of research and development, nanotechnologies are a useful part of the toolset at hand. Quick development of graphene activities in the world of energy is real milestone for this conservative industry.

In that perspective, this talk will try to give an overview of the potential application of graphene that may quickly find usefulness in the energy industry.

At first, we will look at the development of graphene based devices for energy storage, energy transformation, new sensing device through the use of new material based on grapheme or graphene composite for new properties material (catalyst properties, electrochemical advantages, electrical conductivity, thermal transfert)[1].

Then we will try to fill the gap between between existing businesses for example for the gas industry and use of carbon material to produce new by product as grapheme and other high value products.

Finally, we’ll expose through which processes and framework an international industrial group such as ENGIE can become an early adopter of emerging technologies developing specific partnership

References [1]

A. C. Ferrari, “Science and technology roadmap for graphene, related twodimensional crystals, and hybrid systems,” Nanoscale, Sep. 2014.

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April 19-22, 2016 Genoa (Italy)

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Mono and Multilayer Silicene Filed-Effect Transistors E. Cinquanta1, C. Grazianetti1, L. Tao2, P. De Padova3, C. Quaresima3, C. Ottaviani3, B. Olivieri4, D. Akinwande2, and A. Molle1 1Laboratorio MDM, IMM-CNR, via C. Olivetti 2, Agrate Brianza, I-20864, Italy 2Microelectronics Research Centre, The University of Texas at Austin, TX-78758, USA 3ISM-CNR, Via Fosso del Cavaliere 100, Roma, I-00133, Italy 4ISM-ISAC, Via Fosso del Cavaliere 100, Roma, I-00133, Italy eugenio.cinquanta@mdm.imm.cnr.it

Recently, the integration of silicene [1] in a field-effect transistor (FET) [2] attracted huge interest thus representing an intriguing option to overcome the scaling issues in the nanoelectronics field and being, at the same time, fully compatible with the current ubiquitous semiconductor technology. Therefore, the study of Si thin films at the twodimensional (2D) limit is highly demanded in order to understand either structural or electronic properties. In particular, multilayer silicene on Ag(111) [3] might represent an advance with respect to the monolayer because of its weaker interaction with the Ag substrate at the bottom and a higher stability towards air exposure on top. Hence, we report here on the comparison between multilayer silicene films grown at different substrate temperature regimes. By means of Raman spectroscopy, a clear trend of the E2g mode is found out pointing towards bulk-Si condition as the substrate temperature is increased.

Moreover, the realization of multilayer silicene FETs allowed for discriminating an ambipolar behavior from a trivially one as a function of the Si growth temperature [3]. These outcomes show that the structural and electronic properties of Si at the 2D limit can be successfully manipulated through carefully tuning the growth conditions, paving the way to an advanced control of Si properties at the nanoscale.

References [1] [2] [3] [4]

Grazianetti et al., 2D Mater. 3, 012001 (2016).

Tao et al., Nature Nanotech. 10, 227 (2015).

P. De Padova et al. , 2D Mater., 1, 021003 (2014).

Grazianetti et al., in preparation.

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Graphene boosts performance of perovskite photovoltaics Michael Graetzel EPFL, Station 6, Laboratory of photonics and interfaces, Lausanne, Switzerland michael.graetzel@epfl.chl

Due to their high efficiency, low cost and ease of production, metal halide perovskites such as methyl ammonium lead iodide (CH3NH3PbI3) are presently attracting enormous attention as promising candidates for next generation photovoltaics [1]. Owing to their excellent optoelectronic properties, e.g. strong visible light absorption and long charge carrier diffusion length perovskite light harvesting materials are the subject of intense current investigations [2]. We fabricated perovskite solar cells (PSCs) by solution processing with a normal [3] as well as inverted architecture [4] and tested the effect of graphene as electronically active ingredient on device performance. We introduced graphene nano-platelets into the key optoelectronic components of the PSC, i.e. the electron- and hole specific charge extraction layers as well as the pervovskite film itself. We observe substantial benefits for the photovoltaic metrics of the PSC that will be presented in my lecture.

References [1] [2] [3] [4]

M. Gr채tzel, Nature Mat. 13 (2014), 838-842.

D. Bi et al, Science Advances, 2 doi (2016).:10.1126/sciadv.1501170 F. Giordano, A. Abate, J.P. Correa Baena, M. Saliba, T. Matsui, S.H. Im, S.M.Zakeeruddin, M.K. Nazeeruddin, A. Hagfeldt, M. Gr채tzel, Nature Communications, 7 (2016)10379.

W.Chen, et al.. Science (2015) DOI:10.1126/science.aad1015.

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Graphene with triangular perforations Søren Schou Gregersen, Stephen Power, Antti-Pekka Jauho Center for Nanostructured Graphene (CNG) & DTU Nanotech, Ørsteds Plads 344, Kongens Lyngby, Denmark sorgre@nanotech.dtu.dk

Spin-polarization along zigzag edges in graphene systems has been predicted by many theoretical works.[1] Recent experimental progress in fabricating and processing precise edged structures, and in measuring signatures of their edge magnetism,[2] suggest that spintronic devices incorporating zigzag edge magnetism are approaching reality.

Nanopatterning of graphene with perforations, or antidots, has meanwhile been suggested as a route to opening an electronic band gap,[3] and suggested to introduce magnetic properties.[4] In this work, we investigate the electronic and transport properties of zigzagedged triangular antidots using a tight-binding and mean-field Hubbard approach.

Fig. (1) displays one such triangle considered and the associated electronic spin density polarization.

Before spin-polarization is included, we demonstrate that lattices of such antidots display more robust band gap formation than their armchair edged counterparts. Furthermore, unlike traditional antidot systems in graphene, this behavior is independent of superlattice geometry and is more robust against geometric disorders. Fig. (2) shows the density of states of the zigzag edged triangle; notably an armchair edged triangle with a similar superlattice is metallic. Including spin polarization the system becomes half-metallic, where the gap is filled with dispersive spin dependent states. Fig. (3) shows the spin dependent density of states. This opens a whole new range of interesting spin-related applications. Robust spin-filtering and – splitting devices are theoretically realized using arrays of triangular antidots. For example, Fig. (4) shows the spin-polarization of an electric current passing through a nanostructured graphene cross device. The currents flowing to the top and bottom leads are strongly spinpolarized, resulting in a similar spin splitting to that expected for a quantum spin Hall setup.

These findings suggest robust paths to realize nanostructured graphene with a large bandgap or magnetic graphene with half-metallic properties.

References [1] [2] [3] [4]

Son, Y.-W. et al. Nature 444 (2006), 347–349; Yazyev, O. V., et al. Phys. Rev. B 84 (2011) 115406.

Magda, G.Z. et al. Nature 514 (2014), 608–611; Soriano, D. et al. Phys. Rev. Lett. 107 (2011), 1–4.

Pedersen, T.G. et al. Phys. Rev. Lett. 100 (2008), 136804; Power, S.R. et al. Phys. Rev. B 90 (2014), 115408.

Zheng, X.H., et al. 80 (2009), 2–6; Trolle, M. L. et al. Phys. Rev. B 88 (2013), 195418.

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Figures

Figure 1: (1) The electronic spin density polarization (moments, m) around a triangular antidot embedded into graphene. (2) The density of states of the unpolarized triangle shown in (1). (3) The spin-polarized density of states. (4) Transmission current-polarization (PJ) through a nanostructured graphene cross when injecting from the left. (5) A cross section of the electronic currents (J) in (4) along the dashed line between the two first antidot columns.

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New synthesis and applications of graphene based photocatalytic nanocomposites for Healthier Cities Gloria Guidetti1, Alessandro Ianiro1,3, Lucia Lombardi2, Flavia Tomarchio2, H.Friedrich3, E. Pogna6, Nico Sommerdijk3, Boaz Pokroy4, G. Cerullo6 , Andrea Ferrari2, Marco Goisis5, Giuseppe Falini1, Matteo Calvaresi1 and Marco Montalti1 1Department of Chemistry G.Ciamician, University of Bologna, Italy 2Cambridge Graphene Centre, University of Cambridge, Cambridge, UK 3Dep. of Chemical Engineering and Chemistry, Eindhoven University of Technology, ND 4Materials Sceince and Engineering Department Israel Ins. of Technology, Technion, Israel 5CTG Italcementi Group, Bergamo, Italy 6Politecnico of Milan, Milano, Italy gloria.guidetti4@unibo.it

Environmental pollution, especially toxic gases and organics in air and water, caused by anthropic activities, severely threaten ecological balance and human health. To face this problem, during the last decade, the scientific community made lots of efforts in producing compounds (mostly based on semiconductors, e.g.TiO2) that exploit sun light photon energy to photodegradate organic and inorganic pollutants. Recently it has been demonstrated that photocatalytic performances can be enhanced when TiO2 is combined to carbon nanomaterials, Fig.1, e.g. graphene(G) or carbon nanotubes in suitable composite.[1] In this work we synthesized a wide range of G-TiO2 nanomaterials starting from different carbon sources (Graphite, graphene oxide, reduced graphene oxide, CO2 expanded graphite and Graphene water-paste) and using different synthetic pathway (Ultrasonication, ball milling and shearing exfoliation) to promote the interaction between the carbon and the commercial titanium dioxide.

Moreover, we developed a method to test the photocatalytic performance of our graphene based nanocomposites under light irradiation taking two ionic dyes, rhodamine B and fluoresceine, as model targets of organic pollutants. The most promising material, obtained from commercial graphite and TiO2, showed an efficiency increase of Î&#x201D;%P=+20% after 10 min irradiation with respect to bare TiO2.

In order to understand the interaction between the two components as well as the morphology of the sample, we performed TEM microscopy in dry and wet state (FIB-TEM and cryo-TEM), SEM and Raman spectroscopy. In conclusion, exploiting photon energy as well as the interaction with metal oxides and graphene to photodegradate organic and inorganic pollutants, we tried the real application of TiO2-G photocatalytic compounds opening the possibility to have cleaner air

References [1]

N. Zhang, Y. Zhanga and Y. Xu, Nanoscale, 2012, 4, 5792-5813.

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Figures

Figure 1: Scheme of the photocatalytic process of TiO2-G nanocomposite in photodegradation of volatile pollutants.

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Organic Light-Emitting Diode Display Panel Integration Using Graphene Pixel Electrodes Jun-Han Han1, Jin-Wook Shin1 , Nam Sung Cho1 , Hyunsu Cho1 , Jaehyun Moon1, ByoungHwa Kwon1 , Kisoo Kim2 , Suengmin Cho2 , and Jeong-Ik Lee1 1 Electronics and Telecommunications Research Institute (ETRI), Daejeon, Korea 2 Hanwha Techwin R&D Center, Gyeonggi-do, Korea junhan@etri.re.kr

In recent years, significant advances of organic light-emitting diodes (OLEDs) have been made in the active-matrix OLED displays, and OLED has been one of the biggest market leaders in mobile. Furthermore, OLED is expanding its application to large-size display such as both 55-inches and bigger size TVs in the market and the market of the flexible OLED displays as a new trend has been studied and developed. Graphene films are promising for transparent electrode of OLED displays; the superior features of optical transparency and mechanical flexibility give a possibility of alternative to conventional electrode materials [14]. However, the limitations of large area graphene with process compatibility has blocked the way of graphene film application in OLED displays [3].

In this work, we have examined the technical issues for the panel integration and fabricated the OLED display panel with graphene pixel electrodes. As a preliminary to the integration, optical and electrical issues have been addressed in the previous our report [3-4]. In the optical part, the efficiencies, emission distributions and emission spectra of OLEDs with the graphene electrode showed a weaker dependency on the thickness of the organic layers than OLED with the conventional ITO electrode. Because the graphene electrode OLED can offer spectral stability over a wide angle range, graphene emerges as a useful choice in large area OLED in which color uniformity is a concern. As for the electrical issue, interfacial engineering of the graphene electrode such as plasma treatment and insertion of additional layer was needed for better hole injection. As for the last issue to overcome the processability, we have established graphene film patterning process, which do not cause the occurrence of surface defects which affect OLED operation. The OLED with the patterned graphene electrode exhibited comparable performance to the OLED with pristine graphene electrode as shown figure 1.

To investigate the processability of graphene film as OLED display pixel electrodes, we have fabricated the integration substrate with the pixel array of 155 x 60. Each pixel contains the addressing metal line under the planarization layer. The graphene pixel electrodes could be connected to external OLED driver, through trenched via holes, the contact pad and the addressing metal line. The graphene film was synthesized by rapid thermal chemical vapor deposition on rolled copper, and transferred on the planarization layer. Thereafter, the graphene film was patterned into pixel electrodes with size of 170 x 300 Îźm2. Hole transporting layer, emitting layer, electron transporting layer and metal cathode were deposited on OLED display area, sequentially. After the glass encapsulation, we have demonstrated the integrated OLED display panel with the active area of 26 x 26 mm2 as shown figure 2 and 3.

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Despite of extensive attention to graphene by researchers in both industry and academia, there exist many hurdles to overcome to make graphene applicable in OLED display. To this end, we have successfully fabricated the OLED display panel using graphene pixel electrodes and probed the applicability of graphene to OLED displays.

Acknowledgment This work was financially supported by the Development Program of MOTIE/KEIT (10044412, Development of basic and applied technologies for OLEDs with Graphene), Korea.

References [1] [2] [3] [4]

J. Hwang, et Al., Applied Physics Letters, 100 (2012) 133304.

J. T. Lim, et Al., Scientific Reports, 5 (2015) 17748.

J. Moon, et Al., Diamond and Related Materials, 57 (2015) 68-73.

H. Cho, et Al., IEEE JSQTE, 22 (2016).

Figures

(a)

(b)

Figure 1: (a) IVL characteristics and (b) current efficiency of the graphene electrode OLEDs before and after patterning process.

Figure 2: The demonstration of OLED display with graphene pixel electrodes.

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Figure 3: The close-up image: graphene pixel electrodes of integrated graphene OLED display panel.

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Non-invasive Microwave Method for Extended Electrical Measurements on Graphene Ling Hao and J. Gallop National Physical Laboratory, Teddington, TW11 0LW, UK ling.hao@npl.co.uk

As graphene grows in significance for commercial applications it is becoming rather urgent to solve a number of problems associated with industrial scale-up. Most urgent is the requirement for graphene standardization methods, especially for electrical properties. A second missing element in the required developments towards large scale mass-production of high quality graphene is a quick and accurate method of quality control of the electrical properties of graphene which may be applied in, or close to, the graphene growth process.

In this paper we discuss the need for graphene measurement standards while introducing a non-contact method using microwave resonance which we believe solves many of the problems of on-line production quality control.

The method which we are developing at NPL is based on a microwave dielectric resonator system. The graphene to be analysed is brought into the near-field region surrounding the dielectric and the perturbation of the resonatorâ&#x20AC;&#x2122;s centre frequency and linewidth are both measured. We describe the technique, estimate its accuracy and future developments. In essence it relies on three distinct factors. First, although graphene has a high 3D conductivity the 2D sheet resistance of graphene is comparable with the impedance of free space ((ď ­0/ď Ľ0)1/2. Second, a monolayer or even a few-layer thick sample of graphene does not have a significant attenuation effect on electric fields which are parallel to its surface. Third, as a diamagnet, its relative permeability can be assumed to be close to unity.

We have shown that it is possible to convert this technique by a method of substitution, into an accurate and fast method for deriving sheet resistance (or equivalently, 2D conductivity) without the need for patterning or making contacts. We measure first the centre frequency and Q factor of the dielectric resonator on its own, then with a sample of graphene, on a non-conducting substrate, placed nearby and finally with an identical bare substrate in the same position. The presence of the graphene produces a change in Q value (see fig. 1).

These measurements are sufficient to provide accurate determination of the graphene sheet resistance [1]. The reproducibility of our measurements is at the level of a few percent. From comparison of the same measurements made with our microwave technique and conventional van der Pauw measurements on the same samples it is clear that the absolute accuracy is better than 10%. Table 1 indicates a comparison between the two methods.

Agreement is generally very close but note the two methods sample the graphene with somewhat different weighting. We have compared measurement on a range of graphene samples grown by chemical vapour deposition (CVD), high temperature decomposition of SiC and reduction of graphene oxide, having a sheet resistance range of some four orders of magnitude.

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In a recent development we have also demonstrated how we may use an extension of the same technique to measure the graphene mobility and carrier density without the need of electrical contacts. The NPL patented method [2] uses a different microwave mode from the one used for sheet resistance measurements and also requires the application of a modest d.c. magnetic field (~ 0.3T).

For a metal or semi-conductor enclosed within a microwave cavity, with purely diagonal conductivity tensor, the influence of the electric field vector at the conductor’s surface will induce current flow which is parallel to the surface electric field. The main influence on the Q factor of the enclosing cavity is to reduce it, reflecting the additional Joule heating arising from the σ.E local heating. In the presence of a d.c. magnetic field B the conductivity tensor takes on off-diagonal terms (σ is the surface conductivity and E is the local electric field). This leads to a small amount of additional dissipation (remember that generally σxy << σxx) but, more importantly from the point of view of this discussion, the electric field will induce a flow of current orthogonal to the other component and to itself. The orthogonal current pattern of flow over the surface will act as a radiator for the orthogonal degenerate microwave mode.

Detection of the magnetic field dependent amplitude of the radiated power into this orthogonal mode allows determination of the mobility and carrier density. The details of this derivation will be presented in a later publication.

Previously microwave cavity methods have been used to determine the Hall coefficient and hence the mobility of small semiconducting samples. The underlying process is to use a high Q copper cavity (often an ESR spectrometer is used) in which a small semiconducting sample is included. Two advantages apply to our method. First, since we are looking at graphene samples the total volume is extremely small, even though the cross-sectional area may be comparable with that of the microwave resonator. Further, the large area makes calculation and calibration simpler and more accurate. Finally we use a dielectric microwave resonator to which the graphene sample is coupled. Thus there is no first order contribution form the resonator conductivity since it is very close to zero.

More details of recent experimental results from these two methods will be presented, including scanned data over a large area of CVD graphene transferred onto PET substrate which is 300mmx200mm in size.

Acknowledgement: This work was funded by the UK NMS IRD project, EMRP GraphOhm project and EU Graphene Flagship project.

References [1] [2] [3]

L. Hao, J. Gallop, S. Goniszewski, O. Shaforost, N. Klein and R. Yakimova, Appl. Phys.

Lett. 103 (2013) 123103 UK Patent GB1413237.7 O. Shaforost, K. Wang, S. Goniszewski, M. Adabi, Z. Guo, S. Hanham, J. Gallop, L. Hao and N. Klein, J. Appl. Phys. 117 (2015) 024501..

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Figures

Figure 1: TE010 microwave resonance in a 12mm diameter single crystal sapphire resonator. Blues diamonds show response of empty resonator. Pink squares shows response with a bare quartz substrate. Green triangles when graphene coated substrate in same position. Note the large shift in frequency for both bare quartz and graphene coated quartz. But the linewidth only changes due to graphene.

Table 1: Summary of measurement results of 4 nominally identical monlayer CVD graphene samples.

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Development of graphene and related materials in TASC and AIST Masataka Hasegawa TASC Graphene Division, 1-1-1, Higashi, Tsukuba, Ibaraki, 305-8565, Japan AIST Nanomaterials Research Institute, 1-1-1, Higashi, Tsukuba, Ibaraki, 305-8565, Japan hasegawa.masataka@aist.go.jp

TASC, which consists of private companies and AIST, is a research organization for the development of nano-carbon materials. Graphene division of TASC develops graphene and related materials for industrial applications. CVD graphene atomic layer membranes of nanometer thickness, multilayer graphene films of micron thickness by high-temperature treatment of polymers, and exfoliated graphene dispersion from graphite and its integrated films are specifically developed.

Graphene Atomic Layer Membrane by Plasma CVD [1, 2, 3] We have achieved a graphene membrane with a transmittance of 95% (two-layer) for visible light and sheet resistance of 130Ω (gold chloride doped) by developing an original plasma CVD method. In addition, A4- size light transmittance of 92% (3.6 layers) and sheet resistance 500Ω (without doping) have been achieved. The plasma CVD is characterized by highgrowth rate graphene atomic membrane compared with conventional thermal CVD, which is suitable for the high-throughput production for the industrial use. A variety of applications using graphene atomic layer membrane have been being developed by utilizing the characteristics such as electrical conductivity, flexibility, transparency, and chemical resistance.

Multi-layer graphene by high-temperature treatment of polymers By high-temperature treatment at more than 3000°C of polymer thin films we have been developing a synthesis method of multilayer graphene of a thickness of 3μm ~ 100nm. The multi-layer graphene film produced by our method has very high electrical conductivity of 25,000S/cm and thermal conductivity of 2,000W/mK in a planar direction, which are equivalent to single crystal graphite. Along with the synthesis method, we are promoting the development of variety of applications. Exfoliated graphene dispersion and integrated films by liquid phase process By exfoliating graphite in the liquid phase we have been developing a synthesis method of high-quality graphene dispersion at a low cost. In order to enable the mass production we have developed an original exfoliation technique which does not use a high-temperature furnace and dangerous chemicals. We have also developed a forming technique of integrated films from graphene dispersion such as selfsupporting films without binders, and improved the performance of the films, such as electrical conductivity and so on.

This work is mainly based on results obtained from a project supported by New Energy and Industrial Technology Development Organization (NEDO).

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References [1] [2] [3]

R. Kato, K. Tsugawa, Y. Okigawa, M. Ishihara, T. Yamada, M. Hasegawa, Bilayer graphene synthesis by plasma treatment of copper foils without using a carboncontaining gas, CARBON, 77 (2014) 823â&#x20AC;&#x201C;828.

Y. Okigawa, R. Kato, M. Ishihara, T. Yamada, M. Hasegawa, Electrical properties and Domain Sizes of graphene films synthesized by microwave plasma treatment under a low carbon concentration, Carbon, 82(2015) 60-66.

R. Kato, S. Minami, Y. Koga, M. Hasegawa, High growth rate chemical vapor deposition of graphene under low pressure by RF plasma assistance, Carbon, 96 (2016) 1008-1013.

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Optical properties of atomically thin semiconductors layers and heterostructures Tony F. Heinz Depts. of Applied Physics and Photon Science, Stanford University, Stanford, CA 94305, USA and SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA tony.heinz@stanford.edu

We discuss recent advances in our understanding of the optical properties of monolayers of the transition metal dichalcogenide (TMDC) materials, including MoS2, MoSe2, MoTe2, WS2, and WSe2. These materials share several unusual characteristics, including a transition from an indirect-gap material in the bulk to a direct-gap, emissive material at monolayer thickness.

They also exhibit selectivity to excitation of the degenerate K or Kâ&#x20AC;&#x2122; valley under circularly polarized radiation.

In this paper, we highlight progress in understanding two types of interactions in these materials: the many-body interactions between charge carriers in one layer and interactions between carriers that arise when two monolayer sheets of materials stacked on one another to form a bilayer.

The many-body electronic interactions in monolayer TMDC crystals play a central role in defining their optical properties. Here we will stress recent spectroscopic studies in which we have identified the progression of excited exciton states in precise absorption measurements.

This study directly reveals exciton binding energies of several hundred meV. A strongly nonhydrogenic disposition of levels is also observed. The strength of Coulomb interactions is also manifest in high-order excitonic states, including the three-body trion (or charged excitons) and the recently observed four-body biexcitons. Also of note is the possibility of modifying the many-body interactions through carrier doping or through the presence of high densities of excitation.

Another unusual type of interaction associated with these materials concerns the electronic states and transitions expected in stacks of TMDC monolayers. We will present results of studies of the optical response of vertical heterostructures composed of two monolayers the same material (but with an adjustable twist angle) and bilayers of two different crystals. In the latter case, we have identified spectroscopic signatures for rapid charge separation associated with the staggered band structure.

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Vapor Phase Growth of High Quality Monolayer MoS2 at Low Temperature Dake Hu, Liying Jiao* Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, China lyjiao@mail.tsinghua.edu.cn

Two-dimensional (2D) MoS2 atomic layer has received extensive attentions due to its outstanding electrical properties and catalysis activity. However, it remains challenging for synthesizing high quality MoS2 monolayers at temperature lower than 600 oC for its applications in nanoelectronic and optoelectronic devices on various substrates. Here, we present a novel strategy for synthesizing monolayered MoS2 in vapor phase at a growth temperature of 400 oC by optimizing the growth parameters. The obtained MoS2 are mostly monolayered triangular flakes showing high crystallinity with side lengths of ~20 μm. The on/off current ratios and mobility of the field effect transistors (FETs) fabricated on the as made MoS2 were in the ranges of 105−106 and 1.0−2.0 cm2 V−1 s−1, respectively, comparable with those of backgated FETs made with mechanically exfoliated and chemical vapor deposited MoS2 flakes. [1,2] This simple method provides a facile and convenient approach for preparing high quality monolayer MoS2 and opens up a new way for synthesizing other high quality two-dimensional transition metal dichalcogenides.

References [1] [2]

Wang Q H, S. Strano M, et al. Nature nanotechnology, 11 (2012) 699-712.

Wang X S, Jiao L Y, et al. Journal of the American Chemical Society, 14 (2013) 53045307.

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Figures

Figure 1: (a) Atomic Force microscope (AFM) image of the as-made MoS2 flake. (b) High-resolution Transmission electron microscope (TEM) image of MoS2 and selected area electron diffraction (SAED) patterns taken on a typical area of MoS2 flakes (inset). (c) Optical image of a back-gated FET with a MoS2 flake as channel. (d) I ds-Vgs curves for the device in (c).

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Valley Physics in Transition Metal Dichalcogenide 2D crystals Yoshi Iwasa QPEC & Department of Applied Physics, University of Tokyo, Tokyo 113-8656 Japan RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan iwasa@ap.t.u-tokyo.ac.jp

2D crystal of transition metal dichalcogenide (TMD) is a unique spin-orbit system with valley degree of freedom. The monolayer TMD has a honeycomb structure with a multi-valley band structure at the edges of the Brillouin zone, K and K’ points, in a similar manner to graphene.

Due to the absence of in-plane inversion symmetry, the gap is opened providing TMD based 2D crystals with an opportunity of interaction with visible light and thus optical or optoelectronic functions which are basically absent in graphene. Also, the valence band top at the K points are spin split with 0.1 – 0.4 eV due to the large spin-orbit interaction [1]. A peculiar feature of the TMD monolayer is that the K and K’ points have different chirality which can be controlled and detected by various external stimuli such as light, voltage, and magnetic field. In this presentation, a short review will be made on the basic spin-valley and related properties and valleytronic functionalities in TMD materials.

First, we found the valley dependent Zeeman-type out-of-plane spin polarization using spinand angle resolved-photoemission spectroscopy in MoS2 [2], which is fully consistent with a theoretical prediction [1]. This became possible by choosing noncentrosymmetric bulk crystals, so called 3R polytype. Photoluminescence circular dichroism proved that the noncentrosymmetric stacking effectively preserves the information of valley polarization even in multilayers, indicating that the noncentrosymmetric MoS2 crystals are useful materials for the future valleytronics.

Field effect transistor (FET) plays crucial roles in the control of spin-valley degrees of freedom.

We demonstrate FET related new functionalities, including gate-controlled Zeeman-type spin splitting [3], an ambipolar FET [4], and electric field induced superconductivity [5] with an enhanced Pauli pair breaking limit due to the Zeeman-type spin polariation. Finally, we demonstrate the electrically switchable chiral light source, an electro-optical conversion device [6]

References [1] [2] [3] [4] [5] [6]

D. Xiao et al., Phys. Rev. Lett. 108, (2012) 196802.

R. Suzuki et al, Nat. Nano. 9, (2014) 611.

H. T. Yuan et al., Nat. Phys. 9, (2013) 563.

Y. J. Zhang et al., Nano Lett. 12, (2012) 1136, ibid. 13, (2013) 3023.

J. T. Ye et al., Science 338, (2012) 1193.

Y. J. Zhang et al., Science 344, (2014) 725.

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Nonlinear Terahertz Response of Graphene Plasmons Mohammad M. Jadidi1, Jacob C. Konig-Otto2, Stephan Winnerl2, Andrei B. Sushkov1, H. Dennis Drew1, Thomas E. Murphy1 and Martin Mittendorff1 1University of Maryland, College Park, MD 20742, USA 2Helmholtz-Zentrum Dresden-Rossendorf, PO Box 510119, D-01314 Dresden, Germany mmjadidi@umd.edu

Graphene ribbons support terhaertz (THz) plasmon resonances [1] with subwavelength electric field confinement on the graphene surface [2]. The extreme field localization at plasmon resonance greatly increases the light-graphene interaction, and can lead to a strong nonlinear optical response [2,3].

Here we present the first experimental study of the nonlinear response of graphene plasmon resonances and their energy relaxation dynamics. We observe a strong saturation of plasmon absorption in graphene ribbons, using THz pump-THz probe measurements with a free electron laser tuned at the plasmon frequency (9.4 THz). The observed nonlinearity is found to be two orders of magnitude higher than that of graphene with no plasmon resonance. We further present a thermal model for nonlinear plasmonic absorption in graphene ribbons that supports the experimental results. The thermal model suggests that red-shifting and broadening of the plasmon resonance, due to the increase in graphene electron temperature, causes the observed nonlinearity [4].

References [1] [2] [3] [4]

L. Ju, B. Geng, J. Horng, C. Girit, M. Martin, Z. Hao, H. A. Bechtel, X. Liang, A. Zettl. Y. R. Shen, F. Wang, Nat. Nanotechnol. 6.10 (2011).

F. H. L. Koppens, D. E. Chang, F. J. Garc織覺a de Abajo, Nano Lett. 11.8 (2011).

M. Gullans, D.E. Chang, F.H.L. Koppens, F.J. Garc織覺a de Abajo, M.D. Lukin, Phys. Rev. Lett. 111.24 (2013).

M. M. Jadidi, J. C. Konig-Otto, S. Winnerl, A. B. Sushkov, H. D. Drew, T. E. Murphy and M. Mittendorff, arXiv:1512.07508 (2015).

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Figures

Figure 1: (a) Measured and calculated linear transmission spectrum (T) of the graphene nanoribbons array, showing a decreased transmission at the plasmon frequency of 9.4 THz (T0: bare substrate transmission). The inset shows the geometrical parameters of graphene ribbons array on SiO 2/silicon substrate. (b) The red curves show the pump-probe response (â&#x2C6;&#x2020;T/T: relative change of probe transmission) at plasmon resonance when pump and probe were polarized perpendicular to the graphene ribbons (plasmon excited). The blue curves show the response for the same incident pump fluence, but opposite polarization (no plasmon), and the nonlinear response is correspondingly much lower. The dashed theory curves are based on a thermal model for nonlinear plasmonic (red) and Drude (blue) absorption in graphene. (c) Top: Calculated electric field intensity |E|2 at the plasmon resonance of graphene ribbons, relative to the incident plane-wave intensity. It shows a strong field confinement on the graphene that is the origin of the observed plasmonenhanced nonlinearity. Bottom: Peak of relative transmission change vs. pump fluence, that exhibits a square-root dependence.

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Interface engineering by inserting multilayer graphene barrier electrode for low power and highly uniform polymer nonvolatile memory Byung Chul Jang1, Hyejeong Seong2, Jong Yun Kim1,3, Beom Jun Koo1, Sung Kyu Kim4, Sang Yoon Yang1, Sung Gap Im2, Sung-Yool Choi1 1School of Electrical Engineering,Graphene Research Center, KAIST, Daejeon 34141, Korea 2Department of Chemical and Biomolecular Engineering, Graphene Research Center, KAIST, Daejeon 305-701, Korea 3Department of Chemistry, Hanyang University, Seoul 133-701, Korea 4Department of Materials Science and Engineering, KAIST, Daejeon 34141, Korea sungyool.choi@kaist.ac.kr

Recently, as one of the most promising next-generation flexible nonvolatile memory, resistive random access memory (RRAM) has attracted much attention due to its outstanding characteristics. Among various materials for resistive switching, polymer thin films are of significant interest due to its low cost, easy process, and flexibility, but uniformity and reliability issues remain to be addressed. To realize a highly uniform and reliable polymer RRAM, we present a poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane) (pV3D3)based resistive switching memory (RRAM) that can be easily fabricated using the initiated chemical vapor deposition (iCVD), which provides a solvent-free, low-temperature, and damage-free deposition of highly uniform polymer films on various substrates including flexible substrate. The Cu/pV3D3/Al RRAM device has reliable memory performance in terms of retention, but high reset power consumption and nonuniform resistive switching uniformity issues remain to be addressed. To address these problems, we introduced a multilayer graphene (MLG) films into interface of the electrode-polymer in pV3D3-RRAM. The ultralow power consumption is due to the role of Cu diffusion barrier, which suppresses the diffusion of Cu ions through pV3D3 films, resulting in the ultralow reset current by the high out-of-plane resistance of MLG. In addition, the improved switching uniformity is attributed to the effective heat sink by the high thermal conductivity of graphene and the local electric field enhancement at the pV3D3-MLG interface. In addition, the inserted MLG films enabled alternation of resistive switching operation mode form unipolar switching to bipolar switching and caused self-compliance behavior. The innovative strategy using graphene interfacial layer can pave the way of a new application of graphene toward low power consumption and highly uniform polymer nonvolatile memory.

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Conformal Triboelectric Nanogenerator with Graphene Electrode and Their Applications in Wearable electronics Houk Jang, Hyunwoo Chu, Yongjun Lee, Youngcheol Chae, Jong-Hyun Ahn School of Electrical and Electronic Engineering, Yonsei University, Seoul, 03722, Republic of Korea ahnj@yonsei.ac.kr

Recently, the human-machine interfaces as well as the healthcare system have experienced great advancement by the introduction of implanted and skin-mounted electronics.[1] Nevertheless, the power supplying system has not caught up with the technological advances of such electronics. Among the various form of innovative power supplier such as thin-film batteries, wearable solar cells, micro-supercapacitors and wearable thermoelectric, triboelectric nanogenerators (TENGs), which convert the mechanical contact of two different materials into useful electrical power are suitable for the skin-mounted electronics because the mechanical contact is the clean, sustainable and sufficient energy source in daily life or even in a human body.[2] However, the thick thickness of the devices disables the direct integration of the TENGs into a human body, resulting in significant drawbacks in user mobility and sustainability in power supply.

Herein, we introduce the conformal triboelectric nanogenerators (CTENGs) that incorporates into a human body, generating electrical power via contact to the various foreign objects such as clothes and fingers. The thin thickness of the CTEN Youngâ&#x20AC;&#x2122;s modulus of the electrification material enables conformal contact to the uneven surface of the human skin. The modest triboelectric effect of the electrification material was enhanced via simple plasma treatment up to 3800% in terms of effective output power.

Consequently, we present two practical applications of the CTENGs; 1) conformal power generator module that generates electrical power from the contact between fabrics and skin and 2) conformal self-powered interface system that transforms analogous information of human motion into the digital signal. We believe our approaches provides novel routes for the sustainable healthcare system as well as the self-powered interface system.

References [1] [2]

D. â&#x20AC;&#x201C;H. Kim, J. Viventi, et al., Nat. Mater. 9 (2010) 511.

X. Pu, L. Li, H. Song, C. Du, Z. Zhao, C. Jiang, G. Cao, W. Hu, Z. L. Wang, Adv. Mater., 27 (2015) 2472.

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Figures

Figure 1: Optical image of the CTENGs on a forearm. b. The motion through which CTENGs brought into contact with the clothes to generate electicity. c and d. the generated shortcircuit current and open circuit voltage with contact to various fabrics, respectively.

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Metrology of defects and local temperature in graphene Ado Jorio Physics Department, UFMG, Brazil

Raman spectroscopy has been used to evaluate the crystallinity of sp2 carbon materials.

Although defect-induced Raman peaks can be used to quantitatively measure the amount of disorder, they have been hardly used to differentiate types of defects, for example point defects, like vacancies or dopants, against grain boundaries in a poly-domain sample. Here the efforts on this direction will be discussed, including what we have learned from tip enhanced Raman spectroscopy, a technique that brings the optical resolution down to the nanometer scale. Raman spectroscopy is also broadly used to measure local temperature, from the ratio between the anti-Stokes and Stokes scattering. However, correlated Stokesanti-Stokes generation adds another degree of complexity on this protocol, and the use of the Bose-Einstein phonon distribution function has to be generalized. Quantum mechanical calculations including field correlation can be used to quantitatively describe the phenomena.

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Coulomb drag in graphene-based quantumdot heterostructures Kristen Kaasbjerg and Antti-Pekka Jauho Center for Nanostructured Graphene, Department of Micro and Nanotechnology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark kkaa@nanotech.dtu.dk

The phenomenon of Coulomb drag – i.e. a current (or bias) is induced in an unbiased system solely via its Coulomb interaction with a nearby biased system – has been studied extensively in extended systems such as, e.g., 2DEGs and graphene [1]. Only recently was Coulomb drag observed in quantum-dot (QD) systems – in unique graphene-based quantum-dot structures consisting of two capacitively coupled QDs located in separate graphene layers [2,3]. However, while Coulomb drag in extended systems is usually interpreted as momentum transfer between the subsystems, this interpretation does not apply in QD systems. Here, momentum is not a good quantum number, and Coulomb drag is better viewed as an interaction-mediated energy transfer between the QDs. The theoretical description of Coulomb drag in strongly coupled QD systems operating in nonequilibrium conditions is challenging. To this end, we introduce a master-equation approach which accounts for the strong correlations between electrons on the two QDs, higher-order tunneling processes, and energy-dependent couplings to the leads [4]. As we demonstrate, this is essential in order for a complete description of Coulomb drag in coupled QD systems. Importantly, in addition to conventional Coulomb drag in QD systems [5], we uncover additional drag mechanisms which are driven by nonlocal multielectron tunneling processes, and which govern the drag current at low bias voltages.

Studying the Coulomb drag in the graphene-based QD heterostructure illustrated in Fig. 1(a)+(b), we establish (i) the conditions for a nonzero drag current as well as its direction in terms of microscopic system parameters, and (ii) the bias dependence of the drag current across different regimes. Interestingly, we find that the drag current is determined by a nontrivial interplay between the energy dependence of the lead couplings and not the drive current (see Fig. 1(b)+(c)). Finally, we study the fingerprints of the drag mechanisms in the stability diagram which is characterized by the so-called Coulomb diamonds, and show that the predictions of our theory are consistent with the recent experimental observations [2].

References [1] [2] [3] [4] [5]

B. N. Narozhny and A. Levchenko, Rev. Mod. Phys., accepted (2016).

D. Bischoff, M. Eich, O. Zilberberg, C. Rossler, T. Ihn, and K. Ensslin, Nano letters, 15 (2015) 6003.

C. Volk, S. Engels, C. Neumann, and C. Stampfer, Phys. Status Solidi (B), 252 (2015) 2461.

K. Kaasbjerg and A.-P. Jauho, arXiv:1601.00673 (2016).

R. Sánchez, R. López, D. Sánchez, M. Büttiker, Phys. Rev. Lett., 104 (2010) 076801.

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Figures

Figure 1: (a) Illustration of a graphene-based quantum-dot heterostructure consisting of two capacitively coupled graphene. A series of top and bottom gates control the electrostatic potentials on the QDs and the adjacent â&#x20AC;&#x153;bulkâ&#x20AC;? graphene leads. (b) Energy-level diagram of the QD heterostructure showing the QD levels and the alignment of the Dirac cones in the leads. Only the bottom dot is biased. (c) Current through the top dot (the drag current) as a function of the gate voltage on the leads.

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Highly Sensitive NO2 Gas Sensors Based on Electrolytically Exfoliated Graphene/Aucatalyzed WO3 Composite Films Sathukarn Kabcum1, Anurat Wisitsoraat2, Chakrit Sriprachuabwong2, Ditsayut Phokharatkul2, Adisorn Tuantranont2, Sukon Phanichphant3, Chaikarn Liewhiran1,* 1Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand 2Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center, National Science and Technology Development Agency, Klong Luang, Pathumthani 12120, Thailand 3Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand chaikarn_@yahoo.com

The effect of functionalized additives of high-aspect-ratio WO3 nanorods on nitrogen dioxide (NO2) gas-sensing properties were systematically studied by doping with 0.25−2 wt% gold (Au) and additional loading with 0.1−10 wt% electrolytically exfoliated graphene (G). The WO3 nanorods were synthesized by a modified precipitation method [1] utilizing ethylene glycol as a dispersing agent while Au-doped WO3 nanoparticles and their graphene composites were also prepared by impregnation method to achieve high responsive NO2 sensors. Characterizations by X-ray diffraction, transmission/scanning electron microscopy and X-ray photoelectron spectroscopy significantly demonstrated that Au-doped WO3 nanostructures had nanorod-like morphology with polycrystalline monoclinic WO3 phase and Au was confirmed to form solid solution with WO3 lattice while graphene in the sensing film after annealing and testing still retained high-quality multilayer structure with low oxygen content. The sensing films were prepared by spin coating technique and evaluated for low detection of NO2 (0.1255 ppm) sensing performances at operating temperatures ranging from 25C to 350C in dry air. Gas-sensing measurement indicated that WO3 sensing film with optimal 5 wt% graphene exhibited the maximum response at 250C, while 0.5 wt% Au-doped WO3 optimally catalyzed the highest responses and shorter response time at 250C. Particularly, the additional loading of optimal 0.5 wt% graphene into optimal 0.5 wt% Audoped WO3 composites led to a drastic response enhancement with very short response time and fast recovery stabilization at 350C. Detailed mechanisms for the drastic NO2 response enhancement by catalyzed-Au and graphene were proposed based on the formation of graphene/catalyzed Au-doped WO3 ohmic metal-semiconductor junctions and accessible interfaces of graphenemetal oxide nanostructures. Therefore, the GAu/WO3 composite has a potential for responsive low detections of NO2 and may be useful for environmental applications.

References [1]

S. Kabcum, D. Channei, A. Tuantranont, A. Wisitsoraat, C. Liewhiran, S. Phanichphant, Sens. Actuators, B, 226 (2016) 76−89.

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Figures

Figure 1: RESULTS: HR-TEM images of (a) 0.5 wt%Au/WO3 nanorods and (b) graphene (G), change in resistance under exposure to NO2 (0.125−5 ppm) of (c) WO3 and 0.25−2 wt%Au/WO3 at 250°C, (d) 0.1−10 wt%G-loaded WO3 sensors at 250°C, and (e) 0.1−10 wt%G/0.5 wt%Au/WO3 sensors at 350°C.

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Quantification of Defects in Bilayer Graphene

by Raman spectroscopy Martin Kalbac, Sara Costa, Johan Ek Weis, Otakar Frank J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 2155/3, CZ-182 23 Prague 8, Czech Republic

Quantification of defects in carbon nanostructures is crucial for both fundamental science and practical applications. Raman spectroscopy is widely used to determine the number of defects in these materials, because it is non-destructive, fast and relatively easy to interpret.

Here we used oxygen plasma to induce specific amount of defects in graphene samples composed of monolayer, bilayer with Bernal stacked layers and bilayer with randomly stacked (turbostratic) layers. We applied isotopic labelling of graphene layers by 13C, which allowed us to address the Raman bands from the top and bottom graphene layers. Our results suggest that the phonons of the AB stacked bottom graphene layer are scattered by defects in the top graphene layer. Considering this effect we found that monolayer graphene and the top layer of turbostratic bilayer contains similar number of defects, while the top graphene layer of AB stacked bilayer contains fewer defects after a given time of oxygen plasma treatment. This result confirms that the behaviour of the top layer of turbostratic graphene is almost independent on the bottom layer, while the reactivity of the top layer in AB stacked graphene is significantly reduced by interactions with the bottom layer.

Moreover, the phonon â&#x20AC;&#x2DC;scattering efficiencyâ&#x20AC;&#x2122; by the defects in neighbouring graphene layer seems to be dependent on the interactions between graphene layers, which results in the variation of the intensity of the D mode. While in the case of the turbostratic graphene samples this effect leads only to slight increase of the D mode intensity, for the AB stacked bilayer is the intensity of the D mode increased by almost 100%. Consequently, the relation between the Raman signatures of defects and the actual amount of defects in graphene is significantly influenced by a presence of defects in another graphene layer and by the stacking order of these graphene layers.

References [1] [2] [3]

M. Kalbac, Y-P. Hsieh, H. Farhat, L. Kavan, M. Hofmann, J. Kong, and M.S. Dresselhaus: Nanoletters, 10 (11), 4619-4626 (2010).

Martin Kalbac, Ossi Lehtinen, Arkady V. Krasheninnikov and Juhani Keinonen: Adv Mat. 25 (7), 1004-1009 (2013).

Sara D. Costa, Johan Ek Weis, Otakar Frank, Martin Kalbac: Carbon 98, 592-598 (2016).

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Atomically Thin Semiconducting Paper Kibum Kang, Saien Xie, Hui Gao, Kan-Heng Lee, Lujie Huang, Yimo Han, David A. Muller, Jiwoong Park Cornell Univ., Department of Chemistry and Chemical Biology, 116 Baker Lab, Ithaca, NY 14853, USA kk545@cornell.edu

In this talk, I will present a novel material platform, atomically thin semiconducting paper, where â&#x20AC;&#x2DC;paperâ&#x20AC;&#x2122; represents large-scale, atomically-thin, flexible, and freestanding films. To achieve these paper-like semiconducting films, the development of key techniques for uniform large scale growth and stacking of individual semiconducting monolayer films is essential. For this, transition-metal dichalcogenides (TMDs), which can form stable threeatom-thick monolayers and weak interaction with oxide substrates, provide ideal semiconducting materials. First, we recently reported a uniform growth of TMD monolayers with high electron mobility in wafer-scale using metal-organic chemical vapor deposition (MOCVD). Second, we are developing freestanding atomically thin heterostructure films by stacking multiple asgrown films, in which the thickness and composition of the resulting composite is controllable down to sub-nm length scale. We expect these atomically thin semiconducting papers to be applied to flexible, foldable and membrane optoelectronics in the near future.

Figures

Figure 1: a, Schematics of wafer-scale uniform growth of TMD monolayers using MOCVD b, schematics of artificial stacking c, schematics of substrate free, atomically thin, and semiconducting paper.

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Microfluidization of graphite and formulation of graphene-based conductive inks P. G. Karagiannidis, S. A. Hodge, Z. Xu, L. Lombardi, F. Tomarchio, A. Katsounaros, N. Decorde, S. Milana, I. Goykhman, F. Torrisi, A. C. Ferrari Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK acf26@cam.ac.uk

Graphene inks are a rapidly expanding research area [1-2]. Applications include printable antennas [3], and electrodes in (opto)electronic [4] or energy storage devices [5].

However, the current production routes (sonication [6] and high shear-mixing [7]) give low concentrations of few layer graphene (<0.2 mg/ml) [2,7] and require time consuming centrifugation to remove non-exfoliated flakes [2,6,7]. Here we exfoliate graphite in an aqueous surfactant solutions (sodium deoxycholate) using a microfluidic processor (fig.1a).

At a flow rate of 120 ml/min we get 1 mg/ml single/few layers graphene (20% of single layer) with a production rate of 65 mg/h. This rate, for the same energy input (100 MJ/m3), starting graphite concentration (50 mg/ml) and volume (~200 ml) is 50% higher than shear mixing [7] and 1500% times higher than sonication [7]. Unlike sonication or shear mixing, in microfluidization all the material is uniformly exposed to intensive shear, thus the centrifugation step can be avoided and graphene nanoplatelets (GNPs) (mean thickness ~12 nm) can be produced (80 mg/ml at a rate of 7.2 g/h). Conductive inks are formulated by adjusting the viscosity in the range of hundreds of mPas suitable for blade coating, flexographic or screen printing. We employ sodium carboxymethylcellulose (CMC) (fig.1b) as a binder, stabilizer and rheology modifier, reducing the viscosity from 600 mPas at 100 s -1 to 160 mPas at 1000 s-1 (thixotropic behaviour) thus making the ink easier to coat or print.

The inks are used for the fabrication of conductive fibers (fig.1c) using a wet spinning process, coatings (fig.1d) using flexo/screen printing, and aerogels (fig.1e) using freeze drying.

References [1] [2] [3] [4] [5] [6] [7]

A. C. Ferrari et al. Nanoscale 7 4598 (2015).

F. Torrisi et al. ACS Nano 6 2992 (2012).

X. Huang et al. Scientific Reports 5 18298 (2015).

F. Bonaccorso et. al. Nature Phot. 4 611 (2010).

F. Bonaccorso et. al. Science 347 1246501 (2015).

Y. Hernandez et al. Nature Nanotechnology 3 563 (2008).

K. R. Paton et al. Nature Materials 13 624 (2014).

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Figures

Figure 1: a) Microfluidic processing of graphite, b) rheologoy adjustment by CMC and fabrication of c) fibers using a wet spinning process; d) coatings (antennas) using flexo/screen printing; and e) aerogels using freeze drying.

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Highly Flexible Graphene Oxide Nanosuspension Microfluidic Tactile Sensor Kenry1,2,3,#, Joo Chuan Yeo1,3,#, Jiahao Yu3, Menglin Shang3, Kian Ping Loh2,4, Chwee Teck Lim2,3,4 1NUS

Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 2Center for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546 3Department of Biomedical Engineering, National University of Singapore, Singapore 117575 4Department of Chemistry, National University of Singapore, Singapore 117543 5Mechanobiology Institute, National University of Singapore, Singapore 117411 #Both authors contributed equally to this work kenry@u.nus.edu We present a graphene-based liquid-state microfluidic tactile sensor where the sensing platform comprises a graphene oxide (GO) nanosuspension. This nanosuspension fluid serves as the active detection element and is enclosed within an Ecoflex-PDMS microfluidic assembly (Fig.1a). The use of the highly resistive and non-corrosive GO renders the fabricated physical sensor highly sensitive and versatile. The resistive sensor exhibits unique features, such as superior thinness, high flexibility, large area conformability, and small physical size (Fig. 1b). In addition, it displays excellent mechanical deformability and is able to maintain the integrity of the liquid confinement within the microchannel after being subjected to various mechanical deformation. This wearable tactile sensor is also capable of distinguishing a multitude of user-applied mechanical forces, including pressing, stretching, and bending. Additionally, it is possible to identify hand muscle-induced motions, such as finger flexing and fist clenching, using this tactile sensor (Fig. 1c). Our work illustrates the potential of the graphene-based flexible liquid-state sensing platform as a wearable diagnostic and prognostic device for real-time health monitoring.

References [1]

Kenry, J.C. Yeo, M. Shang, J. Yu, K.P. Loh, C.T. Lim, â&#x20AC;&#x153;Highly Flexible Graphene Oxide Nanosuspension Liquid-based Microfluidic Tactile Sensor.â&#x20AC;? Small (2016).

Figures

Figure 1: Highly flexible graphene oxide nanosuspension microfluidic tactile sensor. (a) Actual fabricated GO nanosuspension-based tactile sensor. (b) Distinctive features of the sensor: thin, highly flexible, highly conformable, and small. (c) Wearable device for mechanical force sensing and differentiation.

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An electrophysiological approach to understand the neural interface on micro patterned graphene Sandeep Keshavan1, Shovan Naskar2, Alberto Diaspro1, Laura Cancedda2 & Silvia Dante1 1Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy 2Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy sandeep.keshavan@iit.it

Interfacing cells with 2D single layer graphene (SLG) is essential to exploit the unique properties of this novel material in the biosensor field. Understanding cell behaviour at the graphene surface is therefore a key point for further development and applications. In the present work, CVD grown SLG was transferred onto glass substrates by wet transfer technique [1]. The transferred SLG on the substrate was ablated using a UV laser pulse at 248 nm wavelength to obtain a micro scale patterns; the UV ablated SLG surface was used as a template for the ordered growth of cortical neurons [2]. Raman spectroscopy was used as a tool to judge the quality of SLG transfer and Kelvin probe force microscopy was employed to characterize the surface of the patterned samples. We monitored the in vitro neuronal development on micro patterned SLG coated with an adhesion factor poly-D-lysine (PDL) and we observed that cortical neurons adhered evenly on the substrate, but later the neurons preferentially moved the patterned SLG region, suggesting a better anchorage and migration of neurons patterned SLG surface (Figure 1- C).

We further investigated a developmental study on the efficacy of synaptic transmission on control glass substrates, SLG substrates and on the micro patterned SLG surfaces by recording miniature post synaptic currents (mPSCs) with the help of whole-cell patch-clamp recordings from DIV4 to DIV13 ( Figure 2 ). We observed that in glass substrates, the mPSCs frequencies were very low between DIV4 and DIV8, but presented a significant increase at DIV.On SLG, there was an increasing trend of synaptogenesis, from DIV 7, although this increase was not significant until DIV9. But on patterned samples, synaptogenesis featured differently on patterned SLG and ablated regions. On the patterned-SLG, synaptogenesis increased with increasing DIV. The results obtained were comparable to the data we obtained exclusively with SLG. However, the cortical neurons growing on ablated stripes did not seem to favor functional synaptogenesis. Indeed, synaptogenesis seemed to be extremely scanty until DIV11. These results pave the way for the design of SLG based multi electrode arrays devices, in order to record neural network activity from selected areas of the interface.

References [1]

J. Song, F.-Y. Kam, R.-Q. Png, W.-L. Seah, J.-M. Zhuo, G.-K. Lim, P. K. H. Ho, and L.-L. Chua, “A general method for transferring graphene onto soft surfaces.,” Nat. Nanotechnol., vol. 8, no. 5, pp. 356–62, 2013.

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[2]

M. Lorenzoni, F. Brandi, S. Dante, A. Giugni, and B. Torre, â&#x20AC;&#x153;Simple and effective graphene laser processing for neuron patterning application,â&#x20AC;? Sci. Rep., vol. 3, 2013.

Figures

Figure 1: Confocal micrographs immunostained with DAPI (DNA ) , SMI (Axons ), MAP-2 (-Dendrite ).

Figure 2: Representative traces of mPSCs recorded in whole-cell voltage clamp configuration from cortical neurons at DIV 11.

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Photons, Plasmons and Electrons meet in 2d materials Frank Koppens ICFO, The Institute of Photonic Sciences (Barcelona), Spain

The optoelectronic response of two-dimensional (2D) crystals, such as graphene and transition metal dichalcogenides (TMDs), is currently subject to intensive investigations. Owing to its gapless character, extraordinary nano-photonic properties and ultrafast carrier dynamics, graphene is a promising material for nano-optoelectronics and high-speed photodetectors, whereas TMDs have emerged as potential candidates for sensitive photodetection [1] thanks to their enhanced photon absorption. Vertically assembling these crystals in so-called van der Waals heterostructures allows the creation of novel and versatile optoelectronic devices that combine the complementary properties of their constituent materials.

Here we present a various new device capabilities, varying from quantum nano-photonic devices to ultra-fast and broadband electrical detectors. We applied femtosecond timeresolved photocurrent measurements on 2d material heterostructures, which probes the charge dynamics across TMD and graphene layers directly in the time domain [2,3]. In addition, we apply for the first time infrared photocurrent nanoscopy to high-quality graphene devices[4]. Using this technique, we image the plasmon-voltage conversion in real space, where a single graphene sheet serves simultaneously as the plasmonic medium and detector [5,6].

In addition, we will show working prototype demonstrators of several graphene-based photodetection applications. One tangible example we present is a wearable health monitor that is flexible and transparent, and fully integrated with hybrid graphene-quantum dot detectors. Additionally, we show the progress of monolithic integration of graphene with Si-CMOS electronics for infrared imaging applications (such as night vision).

References [1] [2] [3] [4] [5]

Photodetectors based on graphene, other two-dimensional materials and hybrid systems F. H. L. Koppens et al. Nature Nanotechnol. 9, 780-793 (2014) Picosecond photoresponse in van der Waals heterostructures M. Massicotte et al., Nature Nanotechnology 11 (2016) Photo-thermionic effect in vertical graphene heterostructures. Mathieu Massicotte, Peter Schmidt, FabienVialla, Kenji Watanabe, Takashi Taniguchi, Klaas-Jan Tielrooij, Frank H.L. Koppens. arXiv: 1601.04196 Near-field photocurrent nanoscopy on bare and encapsulated graphene. A. Woessner, Nature Communications (2016).

Thermoelectric detection of propagating plasmons in graphene M.B. Lundeberg et al., arXiv (2016) arXiv:1601.01977

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[6]

Ultra-confined acoustic THz graphene plasmons revealed by photocurrent nanoscopy P. Alonso-Gonzรกlez et al., arXiv (2016) arXiv:1601.0575.

Figures

Figure 1: Electrical detection of propagation graphene plasmons.

Figure 2: Prototype wearable fitness monitor based on graphene.

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Control of WS2 emission properties in 2D-3D semiconductor heterojunctions by band alignment Tilmar Kümmell, Tilmar Kümmell, Wolf Quitsch, Fabian Heyer, Ulrike Hutten, Gerd Bacher Werkstoffe der Elektrotechnik and CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany tilmar.kuemmell@uni-due.de

During the last years transition metal dichalocogenides (TMDCs) have been established as promising building blocks of van der Waals (vdW) heterostructures. In contrast to heterostructures grown by epitaxy, vdW layers can be combined principally without restrictions given by lattice type and mismatch. This opens on the one side fascinating approaches for combining semiconducting TMDCs with other conducting, semiconducting or insulating 2D materials for applications e.g. in nm-thick LEDs, solar cells or photodetectors.

On the other side, 2D materials can serve as tailored functional layers on top of classical bulk semiconductors to implement novel optoelectronic devices [1]. However, experimental research about the impact of semiconducting substrates on TMDC layer luminescence is still at a very initial state: It is not clear, to what extend the classical models describing semiconductor heterojunctions can be transferred to layers with atomic thickness with their specific band structure.

We study mechanically exfoliated WS2 monolayer flakes on GaN substrates with different doping levels for getting fundamental insights into the charge transfer mechanism between 2D materials with a direct bandgap at the K point and 3D materials with a direct bandgap at the Γ point. By using a GaN wide-gap substrate we are able to alter the band alignment between WS2 and the substrate drastically by doping, as the GaN Fermi level can be shifted by more than 1.5 eV between i-GaN and highly p-doped material. An appropriate choice of excitation wavelength allows carrier generation purely in the WS2 layer.

Under green excitation (λ = 532 nm), no significant change of the WS2 photoluminescence (PL) is found for different doping levels (Fig.1, left). The picture is fundamentally different for blue excitation (λ = 405 nm), where the PL is completely quenched in case of a highly pdoped substrate (doping level nearly 1019/cm3 ). In order to explain these findings we have to be aware that by increasing the p doping level, the GaN valence band is shifted energetically above the WS2 valence band at the Γ point, in principle enabling charge transfer from the 2D to the 3D material. In case of excitation at λ = 532 nm, carriers are generated mainly at the K point of WS2. Obviously, charge transfer from the K point of WS2 to the GaN substrate is widely suppressed. In contrast, under blue excitation (λ = 405 nm) a large number of carriers is created close to the Γ point in the Brillouin zone because of the band nesting (inset in Fig. 1) [2]. These holes can apparently overcome the 2D-3D heterojunction in case of p-GaN, strongly quenching the WS2 PL signal. Consequently this carrier transfer mechanism should be blocked by adding an insulating layer between WS2 and the substrate. We confirm this by introducing a 2D insulator (8 nm hBN) beneath the WS2 flake, leading to a recovery of the initial WS2 photoluminescence (Fig. 1 right).

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References [1] [2]

Tsai et al., ACS Nano 8, 8317 (2014).

Kozawa et al., Nat. Comm. 5, 4543 (2014).

Figures

Figure 1: Photoluminescence of WS2 monolayers on top of differently doped GaN substrates.

Excitation was performed close to the K point (λ = 532 nm, left) and close to the Γ point (λ = 405 nm, right) in the band nesting region [2]. The PL signals on p-GaN are measured on the same WS2 flake that partly overlaps with hBN while the other part is in direct contact with the substrate.

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Graphene/Silicon Schottky barrier solar cells Laura Lancellotti1, E. Bobeico1, A. Capasso2,3, E. Lago3, P. Delli Veneri1, N. Lisi2 1ENEA, Portici Research Center, P.le E. Fermi 1, 80055 Portici, Naples, Italy 2ENEA, Casaccia Research Center, I-00123 Rome, Italy 3Istituto Italiano di Tecnologia, Graphene Labs, I-16163 Genova, Italy laura.lancellotti@enea.it

A solar cell based on graphene in direct contact with a semiconductor substrate was proposed for the first time in 2009 [1]; later on, the formation of graphene/semiconductor Schottky barriers was experimentally verified, paving the way to graphene/silicon Schottky barrier solar cells [2].

In the present work, we produced few-layer graphene films by chemical vapor deposition and fabricated graphene/n-silicon solar cells (Fig.1). We increased the cell performance by three optimization steps. After the growth of graphene, we transferred it on pre-patterned silicon substrates with the aid of cyclododecane (i.e., a simple transfer method that preserve the intrinsic features of graphene [3]). We then doped the graphene film with nitrate and chlorine ions to increase its work function and electrical conductivity. Lastly, we deposited a double layer antireflection coating on the top of the device to reduce the optical losses due to the sunlight reflection [4]. The combination of these three optimization steps are reflected in the electrical performance of the solar cell. The optimized device reached a power conversion efficiency of 8.5% exceeding by a factor of 4 that of the undoped and uncoated device. Further investigations on graphene/silicon solar cells will offer the opportunity to attain even higher power conversion efficiencies in devices that are cost-effective and simple to fabricate.

References [1] [2] [3] [4]

S. Tongay, T. Schumann, A. F. Hebard, Appl. Phys. Lett., 95 (2009), 222103.

Y. F. Li, W. Yang, Z. Q. Tu, Z. C. Liu, F. Yang, L. Q. Zhang, R. Hatakeyama, Appl. Phys.

Lett., 104 (2014), 043903.

A. Capasso, M. De Francesco, E. Leoni, T. Dikonimos, F. Buonocore, L. Lancellotti, E. Bobeico, M.S. Sarto, A. Tamburrano, G. De Bellis, N. Lisi, Appl. Phys. Lett., 105 (2014), 113101.

L. Lancellotti, E. Bobeico, A. Capasso, E. Lago, P. Delli Veneri, E. Leoni, F. Buonocore, N. Lisi, Solar Energy, 27 (2016), 198.

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Figure 1: Schematic illustration of the fabricated graphene/silicon solar cell.

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Defects in Two Dimensional Materials: Cooperative Study of HR-TEM and Simulation Gun-Do Lee1, Sungwoo Lee1, Alex W. Robertson2, Qu Chen2, Kuang He2, Chuncheng Gong2, Euijoon Yoon1, Angus I. Kirkland2, and Jamie H. Warner2 1 Department of Materials Science and Engineering, Seoul National University, 151-742, Korea 2 Department of Materials, University of Oxford, Parks Rd, Oxford, OX1 3PH, United Kingdom gdlee@snu.ac.kr

Defects in two dimensional materials have become a subject of intensive investigation because those affect the mechanical and electronic properties of materials. In order to observe and control the defects, many state-of-the-art techniques such as aberration corrected transmission electron microscopy (AC-TEM) have been devoted to the study of the structure and formation process. However, it is very difficult to observe the detail of the formation process even within the state-of-the-art microscopy methods because the dynamics of defective structures such as vacancy, adatom, and edge atoms is completed in very short time. Various simulation methods have been employed to elucidate the hidden process of defect formation and dynamics [1]. In the study of defect formation and dynamics in graphene, we performed the cooperative research of HR-TEM and simulation methods. In the simulation methods, the tight-binding molecular dynamics simulation and density functional theory (DFT) calculation are employed. From the cooperative research, we found the hydrogen-free graphene edges [2], the stability and dynamics of tetravacancy [3], and bridging atom [4] in graphene. In this talk, the role of mediator atoms in two dimensional materials will be introduced in detail and the control of magnetic moment in Fe dopants in graphene [5] will be discussed. If time allows, I will introduce recent results on linear defects in MoS2, graphene partial dislocations [6], and Si atoms at the edge of graphene [7].

References [1] [2] [3] [4] [5] [6] [7]

G.-D. Lee*, C. Z. Wang, E. Yoon, N.-M. Hwang, D.-Y. Kim, and K. M. Ho, Phys Rev Lett 95, 205501 (2005).

K. He, G.-D. Lee, A. W. Robertson, E. Yoon, and J. H. Warner*, Nature Communications 5:3040 (2014).

A. W. Robertson, G.-D. Lee*, K. He, E. Yoon, A. I. Kirkland, and J. H. Warner* Nano Letters, 14, 1634 (2014).

A. W. Robertson, G.-D. Lee*, K. He, E. Yoon, A. I. Kirkland, and J. H. Warner* Nano Letters, 14, 3972 (2014).

Z. He, K. He, A. W. Robertson, A. I. Kirkland, D. Kim, J. Ihm, E. Yoon, G.-D. Lee*, J. H. Warner* Nano Letters, 14, 3766 (2014).

A. W. Robertson*, G-D. Lee, Kuang He, Y. Fan, C. S. Allen, S. Lee, H. Kim, E. Yoon, H. Zheng, A. I. Kirkland, and J. H. Warner*, Nano Letters, 15 5950 (2015).

Q. Chen, A. W. Robertson, K. He, C. Gong, E. Yoon, A. I. Kirkland, G. -D. Lee,* and J. H. Warner* ACS Nano, ASAP (2016).

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Figure 1: AC-TEM image of a bridging atom stabilized trivacancy and the structural model.

Figure 2: Si-C bond at the edge of graphene.

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Graphene Roadmap of Korea and STANDARD GRAPHENEâ&#x20AC;&#x2122;s Products Lee Joung-Hoon STANDARD GRAPHENE Co., Ltd., Korea

This speech has divided into 3 different topics. Firstly, STANDARD GRAPHENE will be talking about the graphene roadmap of Korean government. Secondly, we will briefly talk about STANDARD GRAPHENE, what it is and what it does. And lastly, we will be giving personal thoughts on some of the challenges and future directions of the Graphene industry.

Compared to all other speeches given throughout this conference, this speech will not be as technical but it will be more concentrated on commercial point of view.

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Electron fluid in graphene: Energy Waves, Viscosity, Current Vortices and Negative Nonlocal Resistance Leonid Levitov Massachusetts Institute of Technology, USA

It is widely believed that electrons in charge-neutral graphene form a quantum-critical state that features universal collision-dominated transport resembling that of relativistic viscous fluids. This talk will discuss several new phenomena that provide striking macroscopic signatures of the hydrodynamic regime. One is ballistic propagation of energy in relativistic fluids, which manifests itself as a new collective mode of energy transfer that obeys a wave equation and transports heat rather than charge. It is a sound-like mode, however it is electron-based rather than phonon-based, hence the velocity is quite high. We will demonstrate that a three orders of magnitude enhancement compared to previously investigated phonon-based energy waves is feasible. Another new phenomenon is negative voltage response arising due to vorticity of a viscous electron flow. We argue that the negative voltage response may play the same role for the viscous regime as zero electrical resistance does for superconductivity. Besides offering a diagnostic of viscous transport which distinguishes it from ohmic currents, the sign-changing electrical response affords a robust tool for directly measuring the viscosity-to-resistivity ratio. Lastly, we will discuss the subtle relation between the negative voltage response and vortices, or whirpools, in the electron system, and comment on the recent observation of negative nonlocal resistance in graphene.

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Spin transport in molybdenum disulfide multilayer channel S. H. Liang1, Y. Lu1*, B. S. Tao1, S. Mc-Murtry1, G. Wang2, X. Marie2, P. Renucci2, H. Jaffrès3, F. Montaigne1, D. Lacour1, J.-M. George3, S. Petit-Watelot1, M. Hehn1, A. Djeffal1, S. Mangin1 1Institut Jean Lamour, UMR 7198, CNRS-Nancy Université, BP 239, 54506 Vandœuvre, France 2Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 ave. de Rangueil, Toulouse, France 3Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 1 avenue A. Fresnel, 91767 Palaiseau, France yuan.lu@univ-lorraine.fr

Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications.

However, demonstrating spin-transport through a semiconducting MoS2 channel is challenging. A particular important issue for electrical spin injection is the conductivity mismatch between the ferromagnetic (FM) electrode and the MoS2 channel, which generally results in a vanishing magnetoresistance (MR) due to spin-backflow process by the so-called impedance mismatch problem. In FM/MoS2 contacts, a Schottky barrier height (Φb) 100-180meV is created at the interface with a large charge depletion region. However, it has been recently demonstrated that an effective reduction of Φb down to ~10meV at zero back-gate voltage can be achieved by inserting a 1-2nm layer of MgO [1], Al2O3 [2] or TiO2 [3] as a thin tunnel barrier between the FM and MoS2. A careful design of the interface structure to understand the role of the oxide barrier as well as the Schottky contact is mandatory to get efficient electrical spin injection and detection.

Here we demonstrate the electrical spin injection and detection in a multilayer MoS2 semiconducting channel. A magnetoresistance (MR) around 1% has been observed at low temperature through a 450nm long, 6 monolayer thick channel with a Co/MgO spin injector and detector. From a systematic study of the bias voltage, temperature and back-gate voltage dependence of MR, it is found that the hopping via localized states in the contact depletion region plays a key role for the observation of the two-terminal MR. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel for in-plan spin injection. The underestimated long spin diffusion length (~235nm) and large spin lifetime (~46ns) open a new avenue for spintronic applications using multilayer transition metal dichalcogenides

References [1] [2] [3]

J. R. Chen, et al. Nano Lett., 13 (2013) 3106-3110.

W. Wang, et al. Sci. Rep., 4(2014) 6928.

A. Dankert, L. Langouche, M. V. Kamalakar, and S. P. Dash, ACS Nano, 8 (2014) 476482.

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Figure 1: a, Optical image of the device with the multilayer MoS 2 flake on 100nm SiO2/Si(n++) substrate. b, Magneto-resistance response of the multilayer MoS2 based lateral spin-valve device. c, Schematics of the lateral spin-valve device.

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Modelling of graphene-based sensing devices Elefterios Lidorikis, Nojoon Myoung, Spiros Doukas, Sofia Evangelou, Alva Dakgli Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece elidorik@cc.uoi.gr

Grapheneâ&#x20AC;&#x2122;s optical response is characterized by a constant absorption in the visible-NIR and a large electrical tunability of its plasmonic excitations in the IR spectrum. The light-graphene interactions become even stronger when graphene is integrated into a resonant photonic cavity. In this case, small changes in the graphene doping can alter the coupling condition and shift the optical response, enabling sensitive photodetection and sensing applications [1,2]. We present a numerical optimization study of graphene-based modulation and sensing in two examples. The first involves a plasmonic perfect absorber metamaterial, designed by placing a plasmonic nanoantenna in close proximity (few nm) to a mirror with a dielectric spacer in between. With graphene placed under the antenna, the resonant frequency is modulated according to graphene's doping, providing a promising route to sensitive chemical and biological sensing. The design rules for the metamaterial absorber are explored and we extract a useful general relation between the resonant wavelength and the geometrical features (Fig. 1a). The sensing capability of the metamaterial to the chemical doping of graphene is then evaluated for different metamaterial designs. Our second example involves a recently proposed spectrometer-free setup utilizing nanostructured graphene plasmons [3]. By scanning the graphene electrostatic doping level, the graphene plasmon spectrum shifts through the molecular modes, with the overall absorption peaks revealing the molecular level spectrum (Fig. 1b). We explore here the use of higher-order graphene nanoribbon plasmons to further enhance the resolution and sensitivity compared to what is achieved by the dipole Plasmon This work was funded by the EU Graphene Flagship (contract no.604391) References [1] [2] [3]

F.H.L. Koppens et al., Nature Nanotechnology 9, (2014) 780.

A.C. Ferrari et al., Nanoscale 7, (2015) 4598.

A. Marini et al., ACS Photonics 2, (2015) 876. .

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Figures

Figure 1: (a) optimization map for a metamaterial perfect absorber, (b) overall absorption of a graphene ribbon decorated with an organic monolayer.

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Graphene and graphene oxide for biomedical applications: From stem cell manipulation to antimicrobial applications Chwee Teck Lim1,2,4,5,*, Wong Cheng Lee1,2, Kenry1,2,3, Kian Ping Loh1,3,4 1NUS Graduate School for Integrative Sciences & Engineering, 2Department of Biomedical Engineering, 3Department of Chemistry, 4Centre for Advanced 2D Materials, 5Mechanobiology Institute National University of Singapore, Singapore *ctlim@nus.edu.sg

Among its carbon counterparts, graphene (G) and graphene oxide (GO) display superior functionalities arising from their versatility to tune their electronic, electrochemical, optical, mechanical and thermal properties simply by modifying their lateral dimension, number of layers, stiffness, defect density and chemical composition. However, G and graphene oxide (GO) can also be easily functionalized with various biomolecules and this has led to numerous graphene-related biomedical applications [1-11]. Here we will demonstrate how G and GO can enable us to design and create substrates that can concentrate induction factors thus enabling us to manipulate stem cell fate. Here, the synergy of the unique capability of G and GO and differentiation potential of stem cells can provide exciting opportunities for new and novel therapeutic applications. We will also showcase how the molecular hemocompatibility of G and GO coatings can enable us to endow medical devices with antimicrobial and antithrombotic properties. This is especially useful for devices that have direct and prolonged contact with bodily fluids such as blood or urine. In fact, one of the causes of patient morbidity and mortality is infection and this can arise from prolonged use of invasive medical devices such as catheters. We will explore how G and GO coatings can play their part in minimizing such occurrences.

References [1] [2] [3] [4] [5] [6]

Kenry, J C Yeo, J Yu, M Shang, K P Loh, C T Lim, Highly flexible graphene oxide nanosuspension liquid-based microfluidic tactile sensor, Small, (2016). (in press).

Kenry, KP Loh, CT Lim, Molecular Hemocompatibility of Graphene Oxide and Its Implication for Antithrombotic Application, Small, 38 (2015) 5105-17.

Lee, W C, C H Lim, Kenry, C L Su, K P Loh, C T Lim, Cell Assembled Graphene Biocomposite for Enhanced Chondrogenic Differentiation, Small, 8 (2015) 963-9.

Ng, A M H, Kenry, C T Lim, H Y Low, K P Loh, Highly sensitive reduced graphene oxide microelectrode array sensor, Bionsensors & Bioelectronics, 65C (2014) 265-273.

Ng, A.M.H., Y. Wang, W.C. Lee, C.T. Lim, K.P. Loh, H.Y. Low, Patterning of graphene with tunable size and shape for microelectrode array devices, Carbon, 67 (2014) 390397.

Tang, L A L, J Wang, T K Lim, X Bi, W C Lee, Q Lin, Y-T Chang, C T Lim, K P Loh, High Performance Graphene-Titania Platform for Detection of Phosphopeptides in Cancer Cells, Anal Chem, 84 (2012) 6693-700.

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[7]

Wang, Y, C L Wong, K K Manga, P K Ang, J Lu, Y P Liu, C T Lim, K P Loh, Fluorinated Graphene for Promoting Neuro-Induction of Stem Cells, Advanced Materials, 31 (2012) 4285-4290.

[8] Tang, L A L, W C Lee, H Shi, E Y L Wong, C T Lim, K P Loh, Highly Wrinkled Graphene Oxide Membrane Assembled on Water-Air interface for Spontaneous Stem Cell Differentiation & Supercapacitor Applications, Small, 3 (2012) 423-431.

[9] Ang, P, A Li, M Jaiswal, Y Wang, H W Hou, J Thong, C T Lim, K P Loh, Flow Sensing of Single Cell by Graphene Transistor in a Microfluidic Channel, Nano Letters, 12 (2011) 5240-6.

[10] Lee, W C, C H Y X Lim, H Shi, L A L Tang, Y Wang, C T Lim, K P Loh, The origin of enhanced stem cell growth and differentiation on graphene and graphene oxide, ACS Nano, 9 (2011) 7334â&#x20AC;&#x201C;7341.

[11] Ang, P K, M Jaiswal, C H Y X Lim, Y Wang, J Sankaran, A Li, C T Lim, T Wohland, O Barbaros, K P Loh, A Bioelectronic Platform Using a Graphene-Lipid Bilayer Interface, ACS Nano, 12 (2010) 7387â&#x20AC;&#x201C;7394.

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High performance p-type MoS2 transistor enabled by chemical doping Xiaochi Liu, Deshun Qu, Jungjin Ryu, Faisal Ahmed, Zheng Yang, Daeyeong Lee, and Won Jong Yoo* Samsung-SKKU Graphene/2D Center (SSGC), Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), School of Mechanical Engineering Sungkyunkwan University, 2066, Seobu-ro, Jangangu, Suwon, Gyeonggi-do, 440-746, Korea yoowj@skku.edu The accessibility of p-type MoS2 FET (PFET) has been a stumbling block for complementary device applications involving MoS2.[1] The strong pinning effect at metal-MoS2 interface has been considered to be the leading cause of unipolar n-type MoS2 FET (NFET).[2] In this study, both non-degenerate MoS2 PFET with high on/off ratio (109 at 133K) and gate independent degenerate MoS2 PFET with high hole current density were enabled by controllable chemical doping.[3] Hole mobility of the doped non-degenerate MoS2 PFET was measured to be 72 cm2/Vs at room temperature, and this value is further increased to 132 cm2/Vs at 133K. Channel resistance Rs was proved to limit Ion of PFET after careful analysis of carrier transport mechanism in those doped MoS2 PFETs. Therefore, p-type doping of channel was also necessary for achieving high performance MoS2 PFET in addition to contact engineering.

Based on the high performance PFET, we successfully demonstrated a MoS2 CMOS inverter by integrating NFET and PFET. References [1] [2] [3]

J. Suh, T. E. Park, D. Y. Lin, D. Fu, J. Park, H. J. Jung, Y. Chen, C. Ko, C. Jang, Y. Sun, R. Sinclair, J. Chang, S. Tongay, J. Wu, Nano Lett. 2014, 14, 6976.

W. S. Leong, X. Luo, Y. Li, K. H. Khoo, J. T. L. Thong, ACS Nano 2015, 9, 869.

H. â&#x20AC;&#x201C;M. Li, D. Lee, D. Qu, X. Liu, J. Ryu, A. Seabaugh, W. J. Yoo, Nat. Commun. 2015, 6, 6564.

Figures

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2-D Nanocarbons: Attraction, Reality and Future Zhongfan Liu Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China zfliu@pku.edu.cn

Carbon element has a great number of allotropes, covering the traditional three dimensional (3-D) diamond and graphite, 2-D graphene, 1-D carbon nanotubes and 0-D fullerenes.

Recently, graphyne, a new 2-D carbon allotrope family formed by sp and sp2 hybridization carbon atoms also comes into the stage. Theoretical calculations further indicate that there may exist a penta-graphene, formed by a huge number of carbon pentagons in a 2-D fashion instead of the hexagon structure of graphene. Therefore, 2-D nanocarbons including graphene, graphyne, etc have created a new category of carbon allotropes which attract increasing attentions. We have been working on the controlled synthesis of 2-D nanocarbons for many years. Systematic studies have been done on the chemical vapor deposition (CVD) of high quality graphene on various solid substrates ranging from metals (Cu, Ni, Cu-Ni alloy, Pt, Ru, Rh, Ir, Pd), groups IV-VI early transition metal carbides, to dielectric substrates (h-BN, STO, glass, NaCl). We also made a great effort for the controlled synthesis of graphdiyne, a representative member of the graphyne family. A brief overview will be made in the talk following a general concept of CVD process engineering by highlighting the catalyst design, super graphene glass and scalable production techniques of graphene and various applications as well as the Glaser-Hay coupling synthesis of graphdiyne nanowalls on Cu foils and foams.

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Resonant multiphonon Raman scattering in MoS2 up to the fifth order Tsachi Livneh1* and Jonathan E. Spanier2 1 Department of Physics, NRCN, P.O. Box 9001, Beer- Sheva, 84190, Israel 2 Department of Materials Science & Engineering, Drexel University, 3141 Chestnut St., Philadelphia, PA, 19104, USA T.Livneh@nrcn.org.il

We present a comprehensive multiphonon Raman analysis for bulk and monolayer MoS2 [1].

For the bulk, the analysis consists of symmetry assignment from which we obtain a broad set of allowed second-order transitions at the high symmetry M, K and  Brillouin zone (BZ) points.

We assign about 100 transitions of up to fifth-order processes in the low temperature resonant Raman spectrum measured with excitation energy of 1.96 eV, which is slightly shifted in energy from the A exciton. The main contributions come from four phonons: A1g (M), E12g (M2), E22g (M1) (TA’ (M)) and E22g (M2) (LA’ (M)). The last three are single degenerate phonons at M with an origin of the E12g () and E22g () phonons -see the acoustic phonon branches in the vicinity of M and K points, presented in Fig. 1A [2].

Due to fact that at the M-point only combinations with the same inversion symmetry (g or u) are Raman-allowed, the contribution of combinations with the LA (M) mode are not expected with the above four phonons. Although minor, contributions from K-point and possibly -point phonons are also evident.

Among the four “resonant group” phonons, we identify in the resonant Raman spectra all of the second-order overtones, combination and difference-bands and many of the higherorder bands. An extension (up to ~1530 cm-1) of a recently presented [1] low temperature spectrum is shown in Fig. 1B. A set of calculated frequencies of multiphonon transitions, of all the possible combination bands (within the presented spectral range and up to the forthorder) of n1*E12g (M2)+ n2*A1g (M)+ n3*TA’ (M) + n4*LA’ (M), with n1,n2=0-3, n3,n4=0-2, is depicted with blue bars. They are also presented in the attached table (the 5LA’(M) band is also shown for completeness).

The validation of this multiphonon scheme for 2H-MoS2 is promoted by the excellent agreement between the predicted and measured frequencies and the demonstrated high (with respect to the scheme proposed in Ref. 3) capability to be employed throughout the full spectral range for difference-bands, combination-bands and overtones [1].

References [1] [2]

T. Livneh and J.E. Spanier, 2D Materials 2 (2015), 035003.

C. Ataca, M. Topsakal, E. Akt, and S. Ciraci, J. Phys. Chem. C 115, (2011), 16354.

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Field Effect Transistors with Atomically Precise Graphene Nanoribbons Juan Pablo Llinas1 , Andrew Fairbrother2 , Gabriela Barin2 , Pascal Ruffieux2 , Kyunghoon Lee1 , Byung Yong Choi1,3, Rohit Braganza1 , Zahra Pedramrazi4 , Chen Chen4 , Nicholas Kau4 , Akimitsu Narita7 , Tim Dumslaff6 , Xinliang Feng6 , Klaus M端llen7 , Felix Fischer5 , Michael Crommie4 , Roman Fasel2 , Jeffrey Bokor1 1 Dept. of Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA, USA 2 Empa, Swiss Federal Laboratories for Materials Science and Technology, D端bendorf, CH 3 Flash PA Team, Semiconductor Memory Business, Samsung Electronics Co. Ltd., Korea 4 Dept. of Physics, UC Berkeley, Berkeley, CA, USA 5 Dept. of Chemistry, UC Berkeley, Berkeley, CA, USA 6 Center for Advancing Electronics Dresden, TU Dresden, Dresden, Germany 7 Max Planck Institute for Polymer Research, Mainz, Germany jpllinas@berkeley.edu

Graphene changes from semi-metallic to semiconducting when charge carriers are confined to quasi 1-dimensional graphene nanoribbons (GNRs). The electronic properties of GNRs can be engineered for high performance and low-power semiconducting device applications by varying their width and edge structure. However, traditional methods to pattern GNRs, such as unzipping carbon nanotubes or lithographic techniques, yield GNRs with rough edges which degrade electronic transport. Recently, bottom-up chemical synthesis of graphene nanoribbons with atomically smooth and well-defined edges has been demonstrated [1]. By varying the structure of the monomer used in the polymerization step of the synthesis, the edge structure and width of the GNRs can be controlled. Field-effect transistors (FETs) fabricated with 7 atom wide GNRs (7AGNRs) have shown low driving current of 1 nA for 1 V drain bias due to the large Schottky barrier at the contacts caused by the large band gap of 7AGNRs (~3 eV) [3]. Very-large scale circuit integration requires driving currents that are at least three orders of magnitude larger than this. By measuring the electrical characteristics of FETs with 9 and 13 atom wide GNRs, we demonstrate a two order magnitude improvement in current over the 7AGNRFET. We fabricated field effect transistors using 9-atom and 13-atom wide armchair GNRs (9AGNRs and 13AGNRs, respectively). As previously demonstrated, the synthesis for these GNRs takes place on an Au(111)/mica substrate and the width is defined by the monomer used during polymerization [1],[2]. The quality of the GNRs are verified by scanning tunneling microscope (STM) imaging, as shown in Fig. 1. Fabrication of GNRFETs requires the transfer of GNRs from the Au surface to an insulating surface. We transferred the GNRs by cleaving the mica in 38% HCl and picking up the floating gold film with a 50 nm SiO2 / p++ Si substrate.

Subsequent gold etching yields isolated GNRs on the SiO2 surface. Since the GNRs are only tens of nanometers long, we employed electron beam lithography and lift-off processing to pattern 10 nm thick, 100 nm wide Pd electrodes with ~15 nm channel length. The final device structure is illustrated in Fig 1. Using the same fabrication methods, we made two different chips: one with 9AGNRs and 13AGNRs. Finally, we characterized the electrical transport properties of individual devices.

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For the 9AGNR and 13AGNR chips, 28 devices and 29 devices were fabricated, respectively.

All the devices showed semiconducting behavior with on-off ratios in the range of 102 to 105 and an on-state performance distribution shown in Fig. 2. Both the 9AGNRFETs and the 13AGNRFETs showed similar performance and behavior due to their similar band gap. All the devices are p-type with a positive threshold gate voltage in ambient conditions. However, when the devices are measured in vacuum at room temperature, the threshold voltage shifts towards 0 V as shown in Fig. 2. This effect has been observed in CNTFETs and is attributed to the charge trapping of water molecules in the vicinity of the CNT causing hysteretic effects on the gate control [4]. Since we expect GNRFETs with transparentcontacts to conduct more than 1 A at this bias (as opposed to 100 nA in our devices), we measured the devices in vacuum at varying temperatures to study the transport mechanism at the contacts.

We measured the devices in vacuum at 77 K, 140 K, 210 K, and 300 K. As shown in Fig. 3 there is no noticeable change in conduction at these different temperatures for either 13AGNRFETs or 9AGNRFETs. This weak temperature dependence in conduction indicates the occurrence of tunnelling through the barriers as opposed to thermionic emission over the barriers at the contacts. Tunneling contacts with weak temperature dependence have been observed for CNTFETs and verified via simulations [5].

We demonstrated that both of these types of devices showed significant performance improvement over the previously reported 7AGNRFET and showed no temperature dependence in their behavior. Further work is needed to improve the contact resistance of GNRFETs and to reduce device-to-device variability.

References [1] [2] [3] [4] [5]

Cai, J. et al. Nature 466, 470–473 (2010).

Chen, Y.-C. et al. ACS Nano 7, 6123–6128 (2013).

Bennett, P. B. et al. Applied Physics Letters 103, 253114 (2013).

Kim, W. et al. Nano Lett. 3, 193–198 (2003).

Appenzeller, J., Radosavljević, M., Knoch, J. & Avouris, P. Phys. Rev. Lett. 92, 048301 (2004).

Figures

Figure 1: (a) Schematic of the fabricated GNRFETs. (b), (d) STM image of synthesized 13AGNR and 9AGNR on Au (111). (c) SEM image of the Pd source-drain electrodes.

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Figure 2: (a) I-V characteristics of an 9AGNRFET in vacuum and in ambient conditions. (b) Cumulative distribution function of on-current in our 9AGNRFETs and 13AGNRFETs.

Figure 3: Temperature dependence of I-V characteristics of 9AGNRFET (a) and 13AGNRFET (b).

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Probing spectroscopic properties of BN and black phosphorus layers A. Loiseau1, L.Schué1,2, E. Gaufrès1,3, A. Favron3 , F. Fossard1 , A. Pierret1, J. Barjon2 , F. Ducastelle1, R. Martel3 1 LEM, ONERA-CNRS, Châtillon, France 2 GEMAC, Université Versailles St Quentin – CNRS, Versailles , France 3 RQMP and Département de chimie, Université de Montréal, Montréal, France Annick.loiseau@onera.fr

In this talk, we examine the interplay between structure and spectroscopic properties of both BN and Black Phosphorous (P(black)) mechanically exfoliated layers and how these properties can be further exploited in 2D layered heterostructures, beyond graphene.

Spectroscopic properties were studied using cathodoluminescence (CL) at 4K, Raman spectroscopy, HRTEM and Electron Energy Loss Spectroscopy (EELS) using a monochromated Libra 200 TEM-STEM at 80 kV. Hexagonal boron nitride (h-BN) is a wide band gap semiconductor (~ 6.5 eV), with sp2 hybridation, which meets a growing interest for deep UV LED and graphene and 2D materials engineering [1]. Knowing better the intrinsic properties of this material therefore highly desirable. H-BN displays original optical properties governed, in the energy range 5.5 – 6 eV, by strong excitonic effects, consisting of D and S lines [2]. Thanks to the imaging capability of the CL, emission, related to D lines, is proved to be due to structural defects identified by TEM as grain boundaries or folds. In defect free areas of thin layers, D lines completely vanish and S lines only are observed. S lines are therefore identified as the intrinsic luminescence of the material [2]. We will show how exfoliated layers could be prepared with no D band and that their S-emission dramatically changes when reducing the number of layers, providing with a signature of the 2D confinement and a metrics of the thickness depedence [3]. Low-loss-EELS is an alternative approach to the nature of electronic excitations. One can indeed access to the onset of optical transitions and investigate their angular dependence. We will show that we can probe the whole Brillouin zone of BN layers appropriately cut in a HPHT h-BN single crystal along definite crystallographic orientations and represent the plasmon dispersion as a function of the q momentum [4].

P(black) thin layers have recently raised interest for their original semi-conducting properties, such as tunable direct bandgap and high carrier mobilities. Their study is however very challenging due to its fast degradation under ambient conditions. Thanks to Raman and core-loss EELS spectroscopy, we have investigated the chemistry of degradation and shown that this phenomenon is due to a thickness dependant photo-assisted oxidation reaction with absorbed oxygen in water. This oxidation is consistent with electron transfer model based on quantum confinement. On this basis we carried out appropriate manipulation procedures opening a route to first Raman TEM and Low-loss EELS measurements on pristine mono-, biand multi layers, which will be discussed [5].

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References [1] [2] [3] [4] [5]

C.R. Dean et al. Nature Nanotechnology 5 (2010) 722.

A. Pierret et al, Phys. Rev. B, 89 (2014) 035414.

L. SchuĂŠ et al, submitted 2016.

F. Fossard et al, in preparation (2016).

A. Favron et al, NatureMat.14 (2015)826-832.

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Flexible Graphene Transistors for Bioelectronics Benno M. Blaschke1, Núria Tort-Colet2, Martin Lottner1, Anton Guimerà Brunet3,4, Lionel Rousseau5, Andrea Bonaccini6, Simon Drieschner1, Gaëlle Lissourges5, Rosa Villa3,4, Maria V. Sanchez-Vives2,7 and Jose A. Garrido6,7 1 Walter Schottky Institut und Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany 2 Institut D' Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona 08036, Spain 3 Instituto de Microelectronica de Barcelona (IMB-CNM), CSIC, Campus UAB, 08913 Bellaterra, Barcelona, Spain 4 Centro de Investigacion Biomédica en Red, Biomateriales y Nanomedicina (CIBER-BBN), Spain 5 ESIEE-Paris, ESYCOM, University Paris EST, Cité Descartes BP99, Noisy-Le-Grand 93160, France 6 Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain 7 ICREA, Institució Catalana de Recerca i Estudis Avançats, 08070 Barcelona, Spain benno.blaschke@wsi.tum.de & joseantonio.garrido@icn.cat

Tremendous efforts have been made in the last decades to develop an efficient interface between electronics and living cells. Solution-gated field-effect transistors (SGFETs) based on graphene are a promising technology for this application since they offer a high chemical stability, biocompatibility, low electronic noise as well as high transconductance and thus high sensitivity to electrical changes in the gate. We have already demonstrated that graphene SGFETs on rigid substrates can be used to detect signals from living cells [1, 2].

However, in order to perform in-vivo measurements it is a key requirement to integrate graphene SGFETs on flexible substrates in order to improve the mechanical and electrical contact between the tissue and the transistor and at the same time minimize tissue damage.

In this work we present the fabrication of graphene SGFETs on flexible polymer substrates using high quality CVD graphene. The transistor performance in electrolyte, including the intrinsic electronic noise, is investigated. We compare the performance of flexible and rigid SGFETs and show that the both type of devices exhibit similar transconductance and electronic noise. In addition, we show that the device performance is unaffected by bending the devices both in concave and convex shape. No device degradation is observed when repeated bending is performed.

After successful culture of electrogenic cells on the graphene devices, we demonstrate the successful recording of action potentials of these cells (see Figure 1) using arrays of graphene field-effect transistors. Finally, we will show results from in-vivo recordings using flexible graphene SGFETs in the visual cortex of rats. We demonstrate the electrical recording of brain activity with these transistors and compare their performance to state-of-the art platinum microelectrodes. Our work is an important milestone towards the goal of developing a new generation of neural prostheses based on flexible graphene electronic devices.

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References [1] [2]

L. Hess et al., Small 11, 1703â&#x20AC;&#x201C;1710 (2015).

L. Hess et al., Proceedings of the IEEE 101, 1780 (2013).

Figures

Figure 1: a) Recorded current of flexible graphene solution-gated field-effect transistors showing action potentials of HL-1 cells. b) Zoom into a).

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Novel Electronic and Optical Phenomena in Atomically Thin Quasi-2D Materials Steven G. Louie Physics Department, University of California at Berkeley, and Lawrence Berkeley National Lab,Berkeley, California 94720 U.S.A. sglouie@berkeley.edu

Experimental and theoretical studies of atomically thin quasi two-dimensional (2D) materials and their nanostructures have revealed that these systems can exhibit highly unusual behaviors. Owing to their reduced dimensionality, quasi-2D materials present opportunities for manifestation of concepts/phenomena that may not be so prominent or have not been seen in bulk materials. Symmetry, many-body interaction, and substrate screening effects often play a critical role in shaping qualitatively and quantitatively their electronic, transport and optical properties, and thus their potential for applications. In this talk, we present theoretical studies on quasi-2D systems such as monolayer and few-layer transition metal dichalcogenides and metal monochalcogenides, as well as other 2D crystals going beyond graphene. Several phenomena are discussed, including novel exciton behaviors, tunable electrical transport and magnetic properties, and the important influence of substrate screening. We investigate their physical origins and compare theoretical predictions with experimental data.

This work was supported in part by the National Science Foundation and the U.S. Department of Energy.

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Exfoliated Black Phosphorus: Raman Analysis and Degradation Process in Ambient Conditions A. Favron1 , E. Gaufrès2,3, A.L. Phaneuf4 , F. Fossard3 , P.L. Lévesque2 , N.Y-W. Tang2 , A. Loiseau3 , R. Leonelli1 , S. Francoeur4 and R. Martel2 1 Département de chimie, Université de Montréal, Montréal Canada 2 Département de physique, Université de Montréal, Montréal Canada 3 Laboratoire d’Etude des Microstructures, UMR 104 CNRS-Onera, Châtillons, France 4 Département de Génie Physique, Polytechnique Montréal, Montréal Canada r.martel@umontreal.ca

Black Phosphorus (bP), a lamellar crystal of tetravalent P atoms stacked by weak van der Waals interactions, has attracted interest because two-dimensional confinement leading to high carrier mobility and tunable direct band gap has been observed in exfoliated thin layers. Studying the properties of exfoliated bP is, however, challenging because of a fast degradation upon exposure to ambient conditions. This talk presents experimental insights about the degradation process of bP and covers the various signatures in the Raman spectra of pristine and degraded samples. [1,2] In the first part, we take advantage of a procedure carried out in a glove box to acquire the Raman response of the layers in their pristine states. Raman spectra of mono-, bi- and multilayered bP (Figure 1) show important signatures of layer confinement that can be readily understood using symmetry and mode analyses. In the second part, we investigate the stability and degradation of the layers using TEMEELS, LEEM, AFM and in-situ Raman spectroscopy. The experiments reveal that a combination of oxygen, light and moisture provides the essential ingredients leading to the oxidation of the layers. They also highlight a surprising thickness dependence of this photooxidation reaction, which behavior is consistent with an electron transfer model (redox reaction) that predict a kinetics influenced by quantum confinement. To gain further insights, we probe the influence of this degradation on the wetting properties of thin bP films in different humidity conditions. A statistical analysis of the formation of bubbles at the surface shows a decrease of the wettability of the surface with layer thickness. This behavior is ascribed to the accumulation of phosphoric acid in the bubbles due to degradation. From our analysis of the results and a simple rate equation model, it is found that: i) A threshold humidity is necessary for water condensation; ii) The photo-oxidation occurs on single bubble sites; iii) bP layers immersed in water slowly thickens and crumbles anisotropically due to degradation and water etching. Finally, we show that the level of degradation in ultrathin layers can be directly measured using the Ag1 /Ag2 intensity ratio in the Raman spectra higher the ratio (>0.2) indicates lower degradation level.

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References [1] [2]

A. Favron et al, Arxiv-1408.035v2 (2014).

A. Favron et al., Nature Materials, 14, 826-832 (2015).

Figures

Figure 1: â&#x20AC;&#x201C; Raman spectra of bP layers. Highlighted (inset) is the splitting of the A2g mode and the enhancement of the Raman intensity for the bilayer.

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Direct growth of patterned graphene on dielectric and flexible substrates catalyzed by a sacrificial ultrathin Ni film Miriam Marchena1, Davide Janner1, Tong Lai Chen1, Vittoria Finazzi1, Valerio Pruneri1,2 1 ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain 2 ICREA - Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain miriam.marchena@icfo.es

Direct deposition of graphene on substrates would avoid costly, time consuming and defective transfer techniques. In this paper we used ultrathin films of Ni, with thickness ranging from 5 to 50 nm, as a catalytic surface on glass to seed and promote chemical vapor deposition (CVD) of graphene. Different regimes and dynamics were studied for various parameters including temperature and reaction time. When a critical temperature was reached (Tdewetting), Ni films retracted and holes formed that are open to the glass surface, where graphene deposited. As the temperature raised, dewetting continued leading to formation of metal nanoparticles and large graphene surface coverage. This growth mechanism of graphene on UTMF Ni was demonstrated in this work for temperatures within 700-1000ºC. After CVD, the residual Ni can be etched away and the glass substrate with graphene regains maximum transparency (>90%). As examples, Fig. 1(a) shows the evolution of visible appearance (pictures) of Sample A (5 nm, 900ºC), Sample B (50 nm, 700ºC) and Sample C (50 nm, 1000ºC) after each process step: (first column) Ni as-sputtered, (second column) after graphene deposition and (third column) after Ni removal. This effect is also confirmed in graphs of Fig. 1(b) and Fig. 1(c), where the transmittance and absorbance values at 550 nm are plotted before and after Ni removal. All the results confirm a significant recovery of the samples’ transmittance, in particular sample B with only a residual absorbance of about 3%, very close to the theoretical value of SLG (2.3%).

In this way we could directly grow high quality single layer graphene even at temperatures as low as 700 ºC. The proposed technique has thus the potential to widen the range of substrate materials over which graphene can be directly grown. In the paper, this was demonstrated by depositing graphene patterns on ultrathin, 100 μm thick, sheet of glass with 670 ºC strain point, particularly suitable for flexible electronic and optoelectronic devices (Fig.2).

Graphene was found to be continuous after Ni removal as indicated by SEM characterization (Fig. 2 (c,g-h)) withsheet resistance (Rs) values around 2 kOhm/square, similar to those reported in literature for transferred CVD graphene.

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References [1] [2] [3] [4]

T. Hallam, N. C. Berner, C. Yim and G. S. Duesberg, Adv. Mater. Interf., 1, (2014), 1400115–1400121.

A. Ismach, C. Druzgalski, S. Penwell, A. Schwartzberg, M. Zheng, A. Javey, J. Bokor and Y. Zhang, Nano Lett., 10, (2010), 1542–1548.

C. V. Thompson, Annu. Rev. Mater. Res., 42, (2012), 399–434.

M. H. Ru, A. Bachmatiuk, A. Scott, F. Bo, J. H. Warner, V. Hoffman, J. Lin, G. Cuniberti and B. Bu, ACS Nano, 4, (2010), 4206–4210.

Figures

Figure 1: (a) Picture of Sample A, Sample B and Sample C (Ni 5 nm at 900ºC, Ni 50 nm at 700ºC and 1000ºC, respectively) as deposited (first column), after graphene growth (second column) and after Ni removal (third column). (b-c) Transmittance and absorbance values at 550 nm of the best quality samples before (in black) and after (in red) Ni removal.

Figure 2: Optical images of Ni 50 nm UTMF patterned on Si/SiO2 and Corning® Willow Glass substrates in square shapes of different size (a,e) as deposited via sputtering and (b,f) after Ni removal when graphene is deposited in the same condition as Sample B (50 nm, 700ºC). SEM images in (c, g-h) show high quality graphene squares after Ni removal with absence of any metal residues and holes for both substrates. Au electrodes for Van der Paw electrical measurements are shown in (d).

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Selective Detection of Human & Bird Influenza Virus by Sugar Chain Modified Graphene FET Kazuhiko Matsumoto, Ryota Hayashi, and Takao Ono Institute of Scientific and Industrial Research, Osaka University, Ibaraki-shi, Osaka 567-0047, Japan k-matsumoto@sanken.osaka-u.ac.jp

The bird influenza virus and human influenza virus are selectively detected using the sugar chain modified graphene FET. The bird influenza virus itself is not dangerous and dose not infect to the human. However, once the bird flu get into the body of animals, such as pig, the bird flu changes the structure and get the human adaptability. So, we should know whether the virus has thhalee human adaptability or not.

The influenza virus attached to the sugar chain of the throat of the human and of the colon of the pig. The structure of the each sugar chain is almost the similar between them, but the end of the structures is different, i.e., for the human sugar chain, sialic sugar chain is connected to the ď Ą 2-6 galactose, and for the bird sugar chain, sialic sugar chain is connected to the ď Ą 2-3 galactose. The bird and human influenza virus detect this difference and connect selectively. However, once the bird influenza virus get the human adaptability, it can connect both the bird sugar chain and the human sugar chain also. In order to know whether the influenza virus has the human adaptability or not, the selective detection of bird & human influenza virus is indispensable.

In order to selectively detect the influenza virus, two types of the graphene FET, one is modified by the human type sugar chain, the other is modified by the birds sugar chain, are prepared as shown in Fig.1. The measurement system is shown in Fig.2. For the purpose of the safety, the pseud influenza virus, such as Lectin was used.

Figure 3 shows the selective detection of the pseud human influenza virus. SSA is the Lectin for the pseud human influenza virus, the MAM for the pseud bird influenza virus, and BSA is completely non target protein. In Fig.3, the pseud human influenza virus can be selectively caught by the human-type sugar chain and modified the current of the graphene FET, that means the selective detection of the pseud human influenza virus. Fig. 4 shows the selective detection of pseud bird influenza virus by the bird-type sugar chain modified graphene FET. Thus, we have succeeded in the selective detection of human type and bird type influenza virus by the sugar chain modified graphene FET.

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Figures

Figure 1: Sugar chain modified graphene FET for the selective detection of Bird Flu and Human Ful..

Figure 2: Measurement system

Figure 3: Selective detection of Pseudo Human Flu virus by human sugar chain

Figure 4: Selective detection of Pseudo Bird Flu virus by bird sugar chain

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Commercialising CNTs, Graphene and other 2D Nanomaterials: From the Academic Lab to the Marketplace Ronan McHale, Paul Ladislaus, Dimitris Presvytis, Andy Goodwin Thomas Swan & Co. Ltd., Rotary Way, Consett, Co. Durham, United Kingdom rmchale@thomas-swan.co.uk

Thomas Swan Advanced Materials division is dedicated to the supply of high performance materials which deliver value for our customers in new and emerging technologies, from printable electronics and memory devices to advanced coating and composite systems. We were early investors in carbon nanotubes in collaboration with the University of Cambridge, UK and are now a world leading supplier of high purity single-wall carbon nanotubes (Elicarb速 SW).

More recently, in collaboration with Trinity College Dublin, Ireland, we have developed a novel scalable method for exfoliating graphite in liquids to give large-volume dispersions of graphene nanoplatelets.1 The shear-exfoliation process operates under ambient pressure and temperature conditions, involves no aggressive intercalating and/or oxidation chemistries and is amenable to a wide range of solvent/graphite systems. As such, the product is a pristine, high conductivity graphene nanoplatelet material which is now commercially available in both powder format and as a surfactant stabilised aqueous dispersion (Elicarb速 Graphene). Thomas Swan & Co. Ltd. has engaged numerous partners in application development programmes with this material, targeting a range of technologies including printed electronics, energy storage and capacitive touch sensors. As of early 2016 we will have a production capacity of 15 tonnes per annum of exfoliated 2D nanomaterials.

A further extension of the novel exfoliation process allows access to a wide range of newly emerging 2D advanced materials. In early 2016, Thomas Swan launched a new exfoliated 2D hexagonal boron nitride (h-BN) product. The dielectric nature of h-BN, coupled with high thermal conductivity, good barrier properties, high thermal and chemical stability, and mechanical strength in keeping with that of graphene, promises a wide variety of applications which include thermal interface materials in electronics and gas barrier in coatings and plastics.

This talk will provide an overview of our CNT and graphene products, processes and emerging applications. Further, there will be a focus on our newly emerging h-BN material and the next generation of 2D nanomaterial products.

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References [1]

Paton, K. et al. , Nature Materials, 13 (2014) 624.

Figures

Figure 1: TEM image showing few layer h-BN Nanoplatelets from Thomas Swanâ&#x20AC;&#x2122;s liquid exfoliation process.

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Biomedical applications of graphene: from functionalisation to biodistribution and biodegradation Cécilia Ménard-Moyon CNRS, Institut de Biologie Moléculaire et Cellulaire, Immunopathologie et Chimie Thérapeutique, Strasbourg, France c.menard@ibmc-cnrs.unistra.fr

Since its isolation in 2004, graphene has emerged as a fascinating nanomaterial with unique structural, thermal, mechanical, optical, and electrical properties. Intensive research is ongoing to investigate applications of graphene and graphene oxide (GO) in many fields, including the development of nanoelectronic devices, nanocomposite materials, as well as in biotechnology and nanomedicine. Nevertheless, despite its high potential in various fields, major challenges still remain, in particular related to its low dispersibility in organic solvents and in water, which hampers full exploitation of some of its properties. To counteract this issue, rational functionalisation chemistry is needed to improve processability and impart graphene with novel properties. In this context, GO is an interesting platform for the design of graphene-based hybrid materials. The polar oxygen-containing functional groups of GO render it highly hydrophilic, resulting in a good dispersibility in water and many other solvents.

In addition, the derivatisation of these oxygenated functions is a versatile and effective method to prepare chemically functionalised graphene for a wide range of applications.

Due to the high reactivity of the oxygenated moieties, mainly epoxy, hydroxyl, and carboxyl groups, several derivatisation reactions may occur concomitantly. The reactivity of GO with amine derivatives has been exploited in the literature to design graphene-based conjugates, mainly through amidation. In this talk, I will report our investigations on the reactivity between GO and amine functions, which leads to ring opening of the epoxides, and not to amidation.[2] We also prove using magic angle spinning (MAS) NMR that there is a negligible amount of carboxylic acid groups in GO samples from different sources, hence eliminating the possibility of amidation reactions with amine derivatives.

The outstanding properties of GO and its large surface area offer a variety of opportunities for applications in the biomedical field, such as therapy, imaging, diagnosis, and regenerative medicine. Health impact, biopersistence, and environmental accumulation are key issues for the development of graphene-family nanomaterials in nanomedicine and other related areas. It is thus essential to assess their systematic toxicological effects before their use in different domains. In this context, I will present whole body imaging and pharmacokinetic data following intravenous administration of GO functionalised with a radionuclide in mice.[3] The results show that the thickness of GO is one of the key parameters influencing its pharmacological profile. Understanding human health risk associated with the rapidly emerging graphene-family nanomaterials represents a great challenge because of the diversity of applications and the wide range of possible ways of exposure to this type of materials.

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I will also report our study on the biodegradation of GO by the human myeloperoxidase (MPO) derived from neutrophils.[4] It is fundamental to elucidate the key aspects associated with the biodegradability of graphene-family nanomaterials for their real translation into possible clinical innovations as well as for their safe disposal in the environment. The degradation capability of the enzyme on three different GO samples displaying a variable dispersibility in aqueous media has been compared, revealing that MPO failed in degrading the most aggregated GO sample, but succeeded to completely metabolise highly dispersed GO. I will also present our work on the derivatisation of GO with specific molecules able to enhance the catalytic activity of horseradish peroxidase, leading to accelerated degradation of GO.[5] The results demonstrate that functionalisation can modulate the enzymatic biodegradability of GO. Our finding will certainly help to guide further development of future biomedical applications using GO, for instance by designing biodegradable carriers for drug delivery.

References [1] [2] [3] [4] [5]

K.V. Krishna, C. Ménard-Moyon, S. Verma, A. Bianco, Nanomedicine (Lond.), 8 (2013), 1669.

I.A. Vacchi, C. Spinato, J. Raya, A. Bianco, C. Ménard-Moyon, submitted.

D.A. Jasim,# C. Ménard-Moyon,# D. Bégin, A. Bianco, K. Kostarelos, Chem. Sci. 6 (2015), 3952. (#: these authors contributed equally to this work).

R. Kurapati, J. Russier, M.A. Squillaci, E. Treossi, C. Ménard-Moyon, A.E. Del Rio-Castillo, E. Vazquez, P. Samorì, V. Palermo, A. Bianco, Small 11 (2015), 3985.

R. Kurapati et al., in preparation.

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Graphene biosensors in diagnostics Arben Merkoçi ICREA & Catalan Institute of Nanoscience and Nanotechnology (ICN2), Bellaterra (Barcelona), Catalonia, Spain www.nanobiosensors.org www.icn.cat arben.merkoci@icn.cat

There is an increasing demand for biosensing systems based on simple electrical/optical transducing schemes able to achieve cost efficient detection. Among the various biosensing system performance requirements the high sensitivity and selectivity of the response are crucial for applications in diagnostics. Due to the fact that the analytes to be detected in clinical, environmental or food sample are present in very low concentrations the need for biosensing systems that can detect with high sensitivity and selectivity that include very low detection limits along with high reproducibility is an important challenge. To overcome the difficulties in accomplishing all these requirements the main efforts are driven toward signal amplification and noise reduction of biosensing systems by the incorporation of nanomaterials. Since graphene exhibits innovative mechanical, electrical, thermal and optical properties this two-dimensional material is increasingly attracting attention and it is under active research. Graphene-based materials (GBMs) display advantageous characteristics to be used in biosensing platforms due to their interesting properties such as excellent capabilities for direct wiring with biomolecules, heterogeneous chemical and electronic structure, the possibility to be processed in solution and the availability to be tuned as insulator, semiconductor or semimetal. Moreover, GBMs such as graphene oxide (GO) bears the photoluminescence property with energy transfer donor/acceptor molecules exposed in a planar surface and even can be proposed as a universal highly efficient longrange quencher, which is opening the way to several unprecedented biosensing strategies.

The rational behind the use of GO and GBMs in optical and electrochemical biosensing is being studied and explored. We are developing simple, sensitive, selective and rapid biosensing platforms based on the advantageous properties of GBMs while used as electrochemical transducers or revealing agents in a variety of biosensing systems. Examples related to diagnostics applications including bacteria and other analytes (ex. contaminants) detection will be shown. The developed devices and strategies are intended to be of low cost while offering high analytical performance in screening scenarios beside other applications. Special emphasis will be given to (nano)paper/plastic-based platforms that operate in microarray or lateral flow formats with interest for various detections.

References [1] [2]

E. Morales-Narváez, A. Merkoçi, “Graphene oxide as an optical biosensing platform”, Advanced Materials, Adv. Mater. 2012, 24, 3298–3308.

E. Morales-Narvez, A-R. Hassan, A. Merkoçi, “Graphene Oxide as a PathogenRevealing Agent: Sensing with a Digital-Like Response”, Angwandte Chemie 2013, 52, 13779–13783.

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[3] [4] [5] [6] [7] [8]

A. Fattah, S. Khatami, C. C. Mayorga-Martinez, M. Medina-Sánchez, L. Baptista-Pires, A. Merkoçi, “Graphene/Silicon Heterojunction Schottky Diode for Vapors Sensing Using Impedance Spectroscopy“, Small, 2014, 10, 4193–4199.

E. Morales-Narváez, H. Golmohammadi, T. Naghdi, H. Yousefi, U. Kostiv, D. Horak, N. Pourreza, A. Merkoçi. “Nanopaper as an Optical Sensing Platform”ACS Nano, 2015, 9 (7), pp 7296–7305 E. Morales-Narváez, T. Naghdi, E. Zor, A. Merkoçi, “Photoluminescent Lateral-Flow Immunoassay Revealed by Graphene Oxide: Highly Sensitive Paper-Based Pathogen Detection” Anal. Chem., 2015, 87 (16), pp 8573–8577 A. M. Gravagnuolo, E. Morales-Narváez, S. Longobardi, E. T. da Silva, P. Giardina, A. Merkoçi, “In Situ Production of Biofunctionalized Few-Layer Defect-Free Microsheets of Graphene” Advanced Functional Materials, 2015, 25, 2771–2779 A. M. Gravagnuolo, E. Morales-Narváez, C. R. S. Matos, S. Longobardi, P. Giardina, A. Merkoçi, “Onthe-Spot Immobilization of Quantum Dots, Graphene Oxide, and Proteins via Hydrophobins”, Advanced Functional Materials, 2015, 25, 6084–6092 L. Baptista-Pires, C.C. Mayorga-Martínez, M. Medina-Sanchez, H. Monton, A. Merkoçi, “Water Activated Graphene Oxide Transfer Using Wax Printed Membranes for Fast Patterning of a Touch Sensitive Device”, ACS Nano, Just Accepted Manuscript, DOI: 10.1021/acsnano.5b05963

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Low-frequency modes, twisting- and defectinduced shifts in Raman modes in MoS2, MoSe2, and phosphorene Vincent Meunier Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, USA meuniv@rpi.edu

Beyond graphene materials, such as transition metal dichalcogenides (TMDs) and black phosphorus (or â&#x20AC;&#x153;phosphoreneâ&#x20AC;? at the monolayer limit) have attracted significant attention as emerging 2D materials due to their unique properties compared with well-explored graphene. [1] Compared to graphene, these materials present band gaps that can offer much in terms of potential electronic applications. Many characterization techniques have been employed to improve the understanding of these materials, to establish their crystal structure, purity, number of layers, and internal arrangements (i.e., relative orientation of stacked layers). As a non-destructive and fast technique, Raman has repeatedly proven effective for quantitative determination of these properties. However, many details of the experimental measurements cannot be directly understood from the intuition developed with the vast experience with graphene. Instead, the interpretation of many experimental features requires a dedicated modelling effort based on first-principles methodologies.

Fortunately, at the same time as experimental characterization and sample preparation techniques have evolved to new heights, theoretical schemes are now combined with unprecedented computational resources to provide tools akin to a virtual microscope to enable the translation of experimental data into fundamental understanding of intrinsic properties of the investigated samples. [2] Here, I will summarize how density functional theory and nonresonant Raman scattering methodologies are combined to address many issues that are central to the scientific and technological development of TMDs, phosphorene, and other materials. In particular, I will discuss the importance of lowfrequency modes in the study of layer-layer interactions in TMDs [3] and phosphorene [4], how relative twisting angles can be determined by monitoring relative shifts in Raman active mode in MoSe2 [5], and how Raman can be employed to understand in-plane anisotropy in phosphorene [6,7]. Finally, I will show how defect concentration (notably, S vacancy density) can be determined by the sole knowledge of the shift in major vibration modes of MoS2 subjected to electron irradiation [8].

This work was performed in close collaboration with: Liangbo Liang, Bobby G. Sumpter, Alex Puretzky, and Dave Geohegan, (Oak Ridge National Laboratory), Will Parkin and Marija Drndic (University of Pennsylvania), Xi Ling, Shengxi Huang, and Mildred Dresselhaus (Massachusetts Institute of Technology).

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References [1] [2] [3] [4] [5] [6] [7] [8]

Bhimanapati G.R. et al., Recent Advances in Two-Dimensional Materials beyond Graphene, ACS Nano, 9 (12), pp 11509â&#x20AC;&#x201C;11539 (2015) Liang, L. & Meunier, V. First-principles Raman spectra of MoS2, WS2 and their heterostructures. Nanoscale 6, 5394-5401 (2014) Puretzky, A. et al. Low-Frequency Raman Fingerprints of Two-Dimensional Metal Dichalcogenide Layer Stacking Configurations, ACS Nano 9, 6333-6342 (2015).

Ling, X et al. Low-Frequency Interlayer Breathing Modes in Few-Layer Black Phosphorus, Nano Lett. 15, 4080-4088 (2015).

Puretzky, A. et al. Twisted MoSe2 Bilayers with Variable Local Stacking and Interlayer Coupling Revealed by Low-Frequency Raman Spectroscopy, ACS Nano in press (2016).

Ling, X et al., Anisotropic Electron-Photon and Electron-Phonon Interactions in Black Phosphorus, submitted (2016) Lin, et al. Enhanced Raman Scattering on In-Plane Anisotropic Layered Materials. J. Am. Chem. Soc. 137, 15511-15517 (2015) W. Parkin et al. Raman shifts and in situ TEM electrical degradation of electronirradiated monolayer MoS2, submitted (2016)

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Fabrication and analysis of defective, amorphous, deformed, strained, functionalized and stacked 2D materials via high-resolution electron and scanned probe microscopies Jannik C. Meyer University of Vienna, Physics Department, Vienna, Austria jannik.meyer@univie.ac.at

I will show several recent experiments with 2D materials that have been treated for the generation of defects, synthesized in amorphous form, deformed and strained via local probes, or decorated with molecules. The first part concerns the study of these systems by high-resolution scanning transmission electron microscopy, which reveals structural modifications at the atomic level and also can be used to introduce disorder or even controlled displacements [1-5]. Among other things, we have studied the transition from a crystalline to an amorphous 2D material [2], traced the diffusion of a vacancy in graphene [3], showed a controlled displacement of silicon impurities in graphene [4] and created lateral hetero-structures of ordered and disordered twodimensional carbon [5]. I will also show a new approach to image radiation-sensitive molecular species on graphene, based on distributing the dose over many identical structures [6], besides sandwiching and using low energies. In the second part, I will discuss a novel approach to study free-standing membranes by dual-probe scanning tunneling microscopy (STM), where two STM tips are brought into contact with the graphene membrane from opposing sides. At the closest point, the two tips are separated only by the thickness of the membrane. The interaction of the two probes across the membrane provides insights to both the membrane properties as well as to the fundamental interactions between the probe and the material [7].

We acknowledge funding from the European Research Council (ERC) Project No. 336453PICOMAT and the Austrian Science Fund (FWF) through Grant No. P25721-N20, M1481-N20, and I1283-N20.

References [1] [2] [3] [4] [5] [6] [7]

J. C. Meyer et al., Phys. Rev. Lett. 108, p. 196102 (2012).

F. Eder, J. Kotakoski, J. C. Meyer: Sci. Rep. 4, 4060 (2014).

J. Kotakoski, C. Mangler, J. C. Meyer., Nat. Comm. 5, 3991 (2014).

T. Susi et al., Phys. Rev. Lett. 113, 115501 (2014) J. Kotakoski et al., Nano Lett. 15 p. 5944 (2015).

J. C. Meyer et al., Ultramicroscopy 145 p. 13 (2014).

F. Eder et al., Nano Letters 13, 1934 (2013).

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Room Temperature THz Detection with Thin Layers of Black Phosphorus Martin Mittendorff, Edward Leong, Ryan J. Suess, Andrei B. Sushkov, H. Dennis Drew, and Thomas E. Murphy University of Maryland, College Park, Maryland 20742, USA Martin@Mittendorff.email

Two-dimensional materials attracted interest for optoelectronic devices during the last years.

One of the relatively new, very promising materials that can be exfoliated in the same way as graphene is black phosphorus [1]. Unlike graphene, black phosphorus provides a direct bandgap and therewith enables higher on-off ratios, but at the same time maintaining high carrier mobility. The photo response of thin layers of black phosphorus has been investigated in several studies [2], demonstrating the potential of black phosphorus for near- and midinfrared optoelectronic devices. Moreover, the high mobility of black phosphorus enables intraband absorption of THz photons. Here we present the THz response of an antennacoupled black phosphorus field-effect transistor operating at room temperature.

Thin flakes of black phosphorus were fabricated by mechanical exfoliation from a bulk crystal. 300 nm SiO2 on Si served as substrate for the devices, and electrical connection to the flake was made via a log-periodic antenna for an efficient coupling of the THz radiation to the flake that is of subwavelength dimensions (cf. Fig. 1(a)). To prevent degradation of the flake, a 100 nm thick layer of Al2O3 was deposited on top of the device by atomic-layer deposition [3]. A methanol gas laser served as continuous-wave source at a frequency of 2.5 THz with an average power of about 10 mW at the sample position for the photocurrent measurements. The responsivity of the device depends on the gate voltage (cf. Fig. 1(b)) and the polarization angle of the THz radiation, while the bias voltage has only minor influence on the performance. The responsivity reached a peak value of 80 nA/W at a gate voltage of 10 V, which corresponds to a slightly p-doped regime. We attribute this strong photocurrent to a photothermoelectric effect that has been observed in the near-infrared range recently [4]. With this high THz responsivity, black phosphorus outperforms similar devices based on graphene by more than one order of magnitude [5].

References [1] [2] [3] [4] [5]

L. Li, Y. Yu, G. J. Ye, Q. Ge, X. Ou, H. Wu, D. Feng, X. H. Chen, and Y. Zhang, Nat. Nanotech. 9 (2014) 372–377.

F. Xia, H. Wang, and Y. Jia, Nat. Commun. 5 (2014) 4458.

J. D. Wood, S. A. Wells, D. Jariwala, K.-S. Chen, E.K. Cho, V. K. Sangwan, X. Liu, L. J. Lauhon, T. J. Marks, and M. C. Hersam, Nano Lett. 14 (2014) 6964–6970.

T. Low, M. Engel, M. Steiner, and P. Avouris, Phys. Rev. B 90 (2014) 081408.

M. Mittendorff, J. Kamann, J. Eroms, D. Weiss, C. Drexler, S. D. Ganichev, J. Kerbusch, A. Erbe, R. J. Suess, T. E. Murphy, S. Chatterjee, K. Kolata, J. Ohser, J. C. König-Otto, H. Schneider, M. Helm, and S. Winnerl, Opt. Express 23 (2015) 28728- 28735.

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Figures

Figure 1: (a) Inner part of a log-periodic antenna that is connected to a black phosphorus flake in its center. (b) Gate dependence of the THz induced source-drain current

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Many-body interactions and optical excitations in graphene nanostructures Elisa Molinari and Deborah Prezzi CNR, Istituto Nanoscienze, Modena, Italy, and University of Modena and Reggio Emilia, FIM Department, I-41125 Modena, Italy molinari@unimore.it

Graphene nanoribbons display extraordinary optical properties due to quantumconfinement, such as width-dependent bandgap and strong electron–hole interactions, responsible for the formation of excitons with extremely high binding energies. We show that our ab-initio simulations [1] based on many body perturbation theory (GW+BSE) can provide accurate quantitative predictions of electronic [2] and optical [3] properties in ultranarrow, structurally well-defined ribbons obtained by on-surface synthesis, once substrate effects are properly taken into account.

We further investigate the effects of many-body interactions through guide-function quantum Monte Carlo model calculations, and find huge biexcitonic effects, which are expected to play a role in highintensity photoexcitation regimes. Femtosecond transient absorption spectroscopy measured as a function of the excitation fluence [4], performed in solution on well-characterized nanoribbons [5], indeed shows the impact of enhanced Coulomb interaction on the excited states dynamics: In the highexcitation regime, biexcitons form with high efficiency by nonlinear exciton-exciton annihilation, and radiatively recombine via stimulated emission [4]. The strong stimulated emission signal observed from biexciton states is promising in view of using nanoribbons as active light-amplifying materials, and suggest that also multiple-exciton generation –governed by the same exciton-exciton annihilation ratecan be extremely efficient in these systems.

Multi-particle excitations --excitons and biexcitons--, arising from extreme quantum confinement, thus dominate both the linear and non-linear optical spectra of graphene nanoribbons. A careful description of Coulomb interactions, including edge, substrate and dielectric screening effects, is required for their full understanding.

Work supported in part by MaX – Materials at the Exascale, a European Center of Excellence for High Performance Computing Applications. MaX is an EU H2020 e-Infrastructure: http://www.max-center.eu/

References [1] [2] [3]

D. Prezzi, A. Varsano, A. Ruini, and E. Molinari, Phys. Rev. B 77 (2008) 041404(R).

P. Ruffieux, J. Cai, N. C. Plumb, L. Patthey, D. Prezzi, A. Ferretti, E. Molinari, X. Feng, K. Müllen, C. A. Pignedoli, and R. Fasel, ACS Nano 6 (2012) 6930.

R. Denk, M. Hohage, P. Zeppenfeld, J. Cai, C. A. Pignedoli, H. Söde, R. Fasel, X. Feng, K. Müllen, S. Wang, D. Prezzi, A. Ferretti, A. Ruini, E. Molinari, and P. Ruffieux, Nat. Commun 5 (2014) 4253.

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[4] [5]

G. Soavi, S. Dal Conte, C. Manzoni, D. Viola, A. Narita, Y. Hu, X. Feng, U. Hohenester, E. Molinari, D. Prezzi, K. M端llen, and G. Cerullo, Nat. Commun. 7 (2016) 11010.

I. Verzhbitskiy, M. De Corato, A. Ruini, E. Molinari, A. Narita, Y. Hu, M. G. Schwab, M. Bruna, D. Yoon, S. Milana, X. Feng, K. M端llen, A. C. Ferrari, C. Casiraghi, and D. Prezzi, Nano Letters (2016), DOI 10.1021/acs.nanolett.5b04183, in press.

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All-carbon Solid State Supercapacitors Based on Graphene Nunzio Motta1, Jinzhnag Liu1,2 1 School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, Australia 2 School of Materials Science and Engineering, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China n.motta@qut.edu.au

Graphene-based supercapacitors attracted a lot of interest due to the advantages of graphene over activated carbon and carbon nanotubes (CNTs) in energy storage. This energy storage technology is poised for an explosive growth, due to the high power density and to the flexibility of the material, which can be adapted to a number of applications, from mobile phones to electric cars. Conventional supercapacitors contain metal foils as current collectors, which suffer from corrosion by the acid or alkali electrolyte. We produced all-carbon solid-state supercapacitors using graphene electrodes and double-wall CNT films as current collectors. Though CNTs are relatively inferior compared to graphene in achieving high capacitance, their high electrical conductivity and 1D structure can be useful to rep[lace the metal when combined with graphene for making supercapacitors. The graphene was produced by a simple ultrasound assisted electrochemical exfoliation method. A very low resistance (5 Ω/sq) DWCNT film was coated onto plastic substrates. A thin layer of gelled electrolyte is sandwiched by two electrode films, therefore the whole device is flexible. High capacitance, around 10 mF/cm2, is achieved with an electrode film less than 10 μm in thickness. The energy density of our devices is in the order of 10-3 Wh/cm3, comparable to that of thin film Li battery. The power density is around 10 W/cm3 [1] which is about 10 times higher than other works such as those based on laser-scribed graphene [2].

References [1] [2]

J. Liu, F. Mirri, M. Notarianni, M. Pasquali, and N. Motta, Journal of Power Sources, vol.

274, pp. 823-830, 2015.

M. F. El-Kady and R. B. Kaner, Nature communications, vol. 4, p. 1475, 2013.

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Figures

Figure 1: a), (b) in-plane assembly of two supercapacitors. (c) CV curves measured at 60 mVs -1 for a single, two and four devices in series. (d) CD curves measured at 50 mAcm -2 for a single device, two, and four devices in series.

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Direct Growth of Graphene on Transparent Insulators: Quartz & Silica R. Muñoz, C. Munuera, C. Gomez-Aleixandre, M. Garcia-Hernandez Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain rmunoz@icmm.csic.es

A new method for the direct growth of graphene films on dielectric substrates is reported, using remote electron cyclotron resonance plasma assisted chemical vapor deposition r(ECR-CVD) at low temperature (700ºC). We have devised a two step deposition processnucleation and growth- by changing the process conditions at constant temperature. Up to 500 nm grain sizes are attained for mostly monolayer continuous films exhibiting transmittance larger than 92% and sheet resistance lower to 900 Ω, after low temperature annealing. The grain size and nucleation density of the resulting graphene sheets can be controlled varying the deposition time and pressure. A shelf-limiting character of the process can be conjectured when coalescence of rotational aligned graphene domains takes place and stitching occurs. This method is easily scalable and avoids damaging and expensive transfer steps of graphene films, improving compatibility with current fabrication technologies.

References [1]

Spanish Patent Application: "Deposition of graphene layers by electron cyclotron resonance plasmaassisted chemical vapour deposition" Reference ES1641.1084, R. Muñoz, Cristina Gomez- Aleixandre yM. Garcia Hernandez, 2015.

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Figures

Figure 1: a) AFM image of the deposit in quartz. b) line profile of monolayer flakes. C) Friction force image of monolayer flakes. D) Raman map of the 2D peak. E) Typical Raman spectra on many points show mostlymonolayer grains.

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Three-dimensional, Corrugated Graphene Micro-/Nano-Structures for Advanced Sensor Devices SungWoo Nam Mechanical Science and Engineering, University of Illinois at Urbana-Champaign 1206 W. Green St., MC-244, Urbana, IL 61801, USA http://nam.mechse.illinois.edu swnam@illinois.edu

Superb electromechanical properties of two-dimensional (2D) materials provide a substantial promise for advanced nanoelectromechanical devices, flexible electronics, and wearable bioelectronic devices. In this talk, I present my groupâ&#x20AC;&#x2122;s work on fabrication and processing of crumpled 2D materials-based micro-/nano-structures for advanced optoelectronic and bioelectronic sensors. First, I introduce monolithic synthesis of graphene-graphite for flexible, all-carbon transistor arrays. We demonstrate allcarbon device arrays integrated with various soft and flexible surfaces, including wearable contact lens, for wearable electronics applications. Second, I present a rapid and scalable method of creating crumpled graphene and MoS2 monolayer surfaces by soft-matter transformation of shape-memory polymers as well as swelling-induced integration processes. Third, we further explore optoelectronic applications of crumpled graphene structures by developing mechanically reconfigurable optoelectronic sensors with ca. 500% improved photo-responsivity compared to conventional graphene optoelectronic sensors. Finally, we explore biosensor device applications by constructing an array of field-effect biosensors and interfacing them with muscle and cardiac cells for nano-electrophysiology. I believe our approach to forming crumpled 2D materials-based micro-/nano-structures offers a unique avenue for creating multifunctional sensors, and furthermore, these capabilities could be applied to advanced optoelectronics as well as wearable and conformal electronics in the near future.

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Bottom-Up Solution Synthesis of Graphene Nanoribbons with Tailored Widths and Edge Structures Akimitsu Narita, Yunbin Hu, Matthias Georg Schwab, Bo Yang, Xinliang Feng, Klaus Müllen Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany narita@mpip-mainz.mpg.de

Structural confinement of zero-bandgap graphene into graphene nanoribbons (GNRs) is known to induce opening of the bandgap, which can be modulated depending on their chemical structures such as the width and the edge configuration. Especially, sub-5-nm GNRs with large bandgaps and visible to near-infrared absorption are highly interesting for the nanoelectronic and optoelectronic applications. Whereas the fabrication of sub-5-nm GNRs is highly challenging by top-down methods, we have developed bottom-up approaches for making atomically precise GNRs with the width of ~1-2 nm, based on the synthetic organic chemistry. The GNR synthesis can be carried out from pre-designed monomers with two different methods, namely “in solution” through the conventional polymerization and cyclodehydrogenation reactions as well as “on surface” by annealing on metal surfaces under ultrahigh vacuum conditions.[1,2] While the surface synthesis allows direct visualization of atomically precise GNRs by in-situ scanning probe microscopy, the solution synthesis has an advantage for providing large amount of GNRs for further application.[3,4] Nevertheless, the structures of the available GNRs have been limited, hindering fine-tuning of the properties of the GNRs. We have recently achieved syntheses of a wider variety of structurally defined GNRs with varying width and edge structures, demonstrating modulation of their optical properties.[2] By modulating the monomer design, the width of the GNRs could be increased from ~1 nm up to ~2 nm, which accompanied the decrease of the optical bandgap from ~1.9 eV down to ~1.2 eV (Figure 1).[3,5] GNRs 1-3 featuring different widths could all be synthesized with average lengths over 200 nm, enabling fabrication of transistor devices on single strands of GNRs (1).[4] Furthermore, laterally extended GNR 3 displayed broad absorption over visible into the near infrared region, which allowed spectroscopic investigations over wider range of wavelengths.[5] Further fine-tuning of the bandgap has been accomplished through modulation of the edge structure and structural motif of the GNRs, for instance by involving partial zigzag structures as well as by making GNRs with “necklace-like” structures.[6] These results pave the way toward the application of such bottom-up synthesized sub-5-nm GNRs in next-generation optoelectronic devices.

References [1] [2] [3]

A. Narita, X. Feng, K. Müllen, Chem. Rec., 15 (2015) 295.

A. Narita, X-Y., Wang, X. Feng, K. Müllen, Chem. Soc. Rev., 44 (2015) 6616.

A. Narita, X. Feng, M. Bonn, C. Casiraghi, K. Müllen et al., Nature Chem., 6 (2014) 126.

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[4] [5] [6]

A. N. Abbas, A. Narita, X. Feng, K. M端llen, C. Zhou et al., J. Am. Chem. Soc., 136 (2014) 7555.

A. Narita, M. Bonn, S. De Feyter, C. Casiraghi, X. Feng, K. M端llen et al., ACS Nano, 8 (2014) 11622.

M. G. Schwab, A. Narita, Y. Hu, X. Feng, K. M端llen et al., Chem. Asian J., 10 (2015) 2134.

Figures

Figure 1: Structures of GNRs 1-3 with varying widths from ~1 to ~2 nm.

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Graphene Materials for Advanced Energy Storage Cengiz S. Ozkan Professor of Mechanical Engineering, and Materials Science and Engineering. University of California Riverside, CA 92521 USA

Graphene is a one atom thick two-dimensional material that exhibits exceptional physical and electronic properties, and offers alternatives for applications in energy storage devices, nanoelectronics, spintronics, biosensors, and medicine. I will describe innovative approaches for the design and synthesis of hierarchical three dimensional graphene hybrid materials which possess characteristics including ultra large surface area, tunability, mechanical durability and high conductivity which are appealing to diverse energy storage systems.

Rapid charging and discharging supercapacitors are promising alternative energy storage systems for applications such as portable electronics and electric vehicles. Integration of pseudocapacitive metal oxides with structured nanomaterials has received a lot of attention recently due to their superior electrochemical performance. In order to realize high energy density supercapacitors, we developed a scalable method to fabricate MGM (graphene/MWNT/MnO2) and RGM (graphene/MWNT/RuO2) hybrid systems. The RGM electrode shows outstanding gravimetric and per-area capacitive performance (specific capacitance: 502.78 Fg-1, areal capacitance: 1.11 Fcm-2). The high specific/areal capacitance and extended operational voltage window of 1.5 V lead to an exceptionally high energy density of 39.28 Whkg-1 and power density of 128.01 kWkg-1. Next, I will talk about three-dimensional cone-shape carbon nanotube clusters decorated with amorphous silicon for lithium ion battery anodes. An innovative silicon decorated cone-shape CNT clusters (SCCC) is prepared by depositing amorphous silicon onto CCC via magnetron sputtering.

The seamless connection between silicon decorated CNT cones and graphene facilitates the charge transfer in the system and provides a binder-free technique for fabricating lithium ion batteries. Lithium ion batteries based on this novel 3D SCCC architecture demonstrated a high reversible capacity of 1954 mAhg-1 and excellent cycling stability. Such multi-scale engineered materials could have wide range implications to facilitate new technological innovations in energy storage.

Recent related journal articles [1] [2] [3]

C.S. Ozkan et al., “Bio-Derived, Binderless, Hierarchically Porous Carbon Anodes for Liion Batteries”,Scientific Reports, 5, Article number: 14575, doi:10.1038/srep14575 (2015) C.S. Ozkan et al., “Improved Functionality of Graphene and Carbon Nanotube Hybrid Foam Architecture by UV-ozone Treatment”, Nanoscale, 7, 7045-7050, DOI: 10.1039/C4NR06795A (2015) C.S. Ozkan et al., C. S., Silicon Decorated Cone Shaped Carbon Nanotube Clusters for Lithium Ion Battery Anodes, Small, doi: 10.1002/smll.201400088 (2014)

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[4] [5]

C.S. Ozkan et al., Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors, Scientific Reports, 4, 4452, doi:10.1038/srep04452 (2014) C.S. Ozkan et al., Hybrid carbon nanotube and graphene nanostructures for lithium ion battery anodes, Nano Energy, Volume 3, 113-118 doi: 10.1016/j.nanoen.2014.07.013 (2014)

Figures

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System-Level Applications of Two-Dimensional Materials: Challenges and Opportunities L. Yu, A. Nourbakhsh, H. Wang, Y. Lin, A. Hsu, E. McVay, M. Hempel, S. Ha, D. Reda ElDamak,C. Mackin, M. Dubey, M. Dresselhaus, A. Chandrakasan, J. Kong, and Tomás Palacios Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Bldg. 36-567B, Cambridge, MA 02139, USA tpalacios@mit.edu

Two dimensional materials represent the next frontier in advanced materials for electronic applications. Their extreme thinness (3 or less atoms thick) gives them great mechanical flexibility, optical transparency and an unsurpassed surface-to-volume ratio. At the same time, this family of materials has tremendously diverse and unique properties. For example, graphene is a semimetal with extremely high electron and hole mobilities, hexagonal boron nitride forms an almost ideal insulator, while MoS2 and other dichalcogenides push the limits on large area semiconductors.

The successful growth of these materials over large areas has allowed their use in numerous systemlevel demonstrators. For example, the zero bandgap of graphene and its ambipolar conductivity has been used in a wide variety of rf and mixed applications, including frequency multipliers, mixers, oscillators and digital modulators [1]. At the same time, the wide bandgap of MoS2 and WSe2 in combination with advanced fabrication technology has enabled its use in memory cells, analog to digital converters and ring oscillators with orders of magnitude better performance than other materials for large area applications [2]. These and other examples [3] will be discussed to highlight the numerous new opportunities of 2D materials.

Acknowledgements. This work has been partially funded by the MIT-Army ISN program, ARL and theONR PECASE project.

References [1] [2] [3]

Fiori, G., F. Bonaccorso, G. Iannaccone, T. Palacios, D. Neumaier, A. Seabaugh, S. K. Banerjee, and L. Colombo, “Electronics based on two-dimensional materials,” Nat. Nanotechnol., vol. 9, no. 10, pp. 768–779, Oct. 2014.

Yu, L., A. Zubair, E.J. G. Santos, X. Zhang, Y. Lin, Y. Zhang, T. Palacios, “HighPerformance WSe2 Complementary Metal Oxide Semiconductor Technology and Integrated Circuits,” Nano Lett., vol. 15 (8), pp. 4928–4934, July 2015.

Hsu, A., P.K. Herring, N.M. Gabor, S. Ha, Y.C. Shin, Y. Song, M. Chin, M. Dubey, A. Chandrakasan, J. Kong, P.J. Herrero, T. Palacios, “Graphene-Based Thermopile for Thermal Imaging Applications,” Nano Lett., vol. 15 (11), pp 7211–7216, Oct. 2015.

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Figures

Figure 1: Different examples of system-level applications of two-dimensional materials. a) flexible chemical sensor based on graphene; b) digital circuit fabricated on a MoS 2 layer; and c) mid-infrared image obtained with a graphene imager.

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Scale-dependent fragmentation mechanism of two-dimensional materials Andrea Liscio1, Konstantinos Kouroupis-Agalou1, Alessandro Kovtun1, Emanuele Treossi1, Nicola Maria Pugno2, Giovanna De Luca3,Vincenzo Palermo1 1 CNR-ISOF Istituto per la Sintesi Organica e la Fotoreattività-Consiglio Nazionale delle Ricerche Bologna, Italy 2 Dipartimento di Ingegneria Civile, Ambientale e Meccanica,Università di Trento, Trento, Italia 3 Dipartimento di Scienze chimiche, biologiche, farmaceutiche e ambientali, Università di Messina, Messina, Italy palermo@isof.cnr.it

The physics of fragmentation is of interest for different fields of science and engineering; the size distribution of 3-dimensional (3D) fragments is typically studied in materials science, military applications or astronomy; size distribution of (1D) polymer chains is studied instead in polymer science. Here, we model the physics of fragmentation in two dimensions (2D) using as an ideal system graphene oxide monoatomic nanosheets. Thanks to automatic image processing and statistical modelling we are able to discriminate two different fragmentation processes in 2D: “bulk” fragmentation and “edge” fragmentation, acting on different scales, following gamma and exponential distributions respectively. We can define in this way the area polydispersity in two dimensions and demonstrate (in analogy with polymer metrology) that this parameter is proportional to light scattering of 2D materials in solution.

References [1] [2] [3] [4] [5] [6]

V. Palermo, I. Kinloch, N. Pugno, S. Ligi, Advanced Materials, accepted.

D. Pierleoni, Z.Y. Xia, M. Christian, S. Ligi, M. Minelli, V. Morandi, F. Doghieri, V. Palermo Carbon, 96, 503 (2016) P. Samorì, I.A. Kinloch, X. Feng, V. Palermo 2D Materials, 2, 030205 (2015) Vianelli, A. Candini, E. Treossi, V. Palermo, M. Affronte Carbon, 89, 188 (2015) M. Melucci, S. Ligi, V. Palermo Materials Matters-Sigma Aldrich, 11, 45 (2015) Kouroupis-Agalou, A. Liscio, E. Treossi, L. Ortolani, V. Morandi, N.M. Pugno, V. Palermo, Nanoscale, 6, 5926, 2014.

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Figures

Figure 1: a1 A) Schematic representation of one of the different fragmentation mechanisms observed. B) Evolution of size distribution of the 2D nanosheets for different sonication times, plotted in log-log scale.

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Graphene-based large area dye-sensitized solar cell module Alessandro L. Palma1 ,Simone Casaluci 1, Babak Taheri1, Mauro Gemmi2, Vittorio Pellegrini3, Aldo Di Carlo1and Francesco Bonaccorso3 1 CHOSE - Center for Hybrid and Organic Solar Energy, Dept. Electr. Eng. University of Rome "Tor Vergata", Via del Politecnico 1, 00133, Rome, Italy 2 Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy 3 Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, 16163 Genova, Italy simone.casaluci@uniroma2.it

In this work, we report the use of graphene nanoflakes, produced by liquid phase exfoliation of graphite [1], as a catalyst material for the realization of large area dye-sensitized solar cell (DSSC) module. We report the electrochemical performances of graphene flakes-based ink used as counter electrode in small area DSSCs targeting the replacement of the standard catalyst material i.e., platinum [2], an expensive noble metal. Our results demonstrate that pristine graphene flakes can be used as catalyst, offering advantages in term of cost, scalability and easier production/processing with respect to other low-dimensional materials such as reduced graphene oxide, which require post-processing treatments, and carbon nanotubes, transition metal di-chalcogenides and oxides, etc., which are instead expensive if compared with pristine graphite. The graphene-based ink was spray coated onto FTO-glass substrate to obtain a large area (>90cm2 ) semi-transparent (transmittance 44%) counterelectrode[3]. As a proof of concept, we have fabricated the first graphene-based large area (43.2 cm2 active area) DSSC Z-type connection module with ad-hoc vertical contacts layout, exhibiting a power conversion efficiency (PCE) of 3.5% at 1 Sun and 4.6% at 0.17 Sun. The graphene-based DSSC module demonstrated good response to diffuse light and low illumination conditions[3]. We have also demonstrated the viability of our approach on flexible substrates. We spray coated graphene-based ink onto a PET-ITO used as front electrode in flexible DSSC. A fine tuning between efficiency and transparency was carried out to optimize the PCE of the cells. These results pave the way for the realization of allprinted and (semi)transparent graphene based large-area and cost-effective DSSCs on arbitrary substrates by proving the possibility of enhancing the performance of large area printed DSSCs, under ambient conditions, upon the exploitation of graphene-based inks.

References [1] [2] [3]

F. Bonaccorso, A. Lombardo, T. Hasan, Z. Sun, L. Colombo and A. C. Ferrari, Mater.

Today, 15 (2012) 564-589 B. O'regan and M. Gr채tzel, Nature, 353 (1991) 737-740 S. Casaluci, M. Gemmi, V. Pellegrini, A. Di Carlo, and F. Bonaccorso, Nanoscale, 8, (2016), 5368.

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Figures

Figure 1: Spray coating of graphene-based ink for the realization of DSSC modules. The as produced module has shown a PCE of 3.5%.

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Tensile tests on single graphene layers Maria F. Pantano1, Giorgio Speranza,2,3,4, Nicola M. Pugno 1,2,5 1 Laboratory of Bio-Inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy 2 Center for Materials and Microsystems, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (TN), Italy 3 Istituto Fotonica e Nanotecnologie â&#x20AC;&#x201C; CNR, via alla cascata 56, 38123 Trento, Italy 4 Department of Material Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy 5 School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K. nicola.pugno@unitn.it

Owing to its outstanding electrical, mechanical, optical and thermal properties, graphene is considered the key material for next generation electronics [1-2]. The design of high performance yet reliable devices requires a deep understanding of its mechanical behavior.

Unfortunately, while a number of computational and theoretical studies have been proposed [3-5], up to date availability of experimental data is still limited, with no information about graphene strength measured through a tensile test. In fact, the unique 2D topology of such material while being the key to its unprecedented behavior poses many issues to successful testing. For example, it is challenging to manipulate completely free-standing samples and fix them for a standard tensile test.

In the present paper we address such main issue through the fabrication of a novel device able to perform direct tensile tests on samples, like single atomic layers, initially deposited onto a substrate. In order to demonstrate the validity of the present device, this is first applied for the mechanical characterization of micro and nanospecimens, such as aluminum microwires (18 Âľm diameter) and ultra thin films (800 nm thickness). The results derived from our device are then compared to those obtained through a commercial nanotensile testing machine, showing good agreement. Finally, the device is applied for tensile testing of a single graphene layer, providing results in good agreement with the predictions of atomistic simulations and nano indentation membrane experiments (see review [6]).

References [1] [2] [3] [4] [5] [6]

AK Geim, KS Novoselov, Nature Materials 6 (2007) 183-191.

J Zhang, S Ryu, NM Pugno, Q Wang, Q Tu, M Buehler, X Zhao, Nature Materials 12 (2013) 321-325.

OV Yazyev,YP Chen, Nature Nanotechnology 9 (2014) 755-767.

NM Pugno, RS Ruoff, Philosophical Magazine 84 (27) (2004) 2829-2845.

J Han, NM Pugno, S Ryu, Nanoscale 7 (2015) 15672-15679.

A Ferrari, et al., Nanoscale 7 (2015), 4598-4810.

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Spatial Nonuniformity of WS2 Monolayers I. Paradisanos1,2*, N. Pliatsikas3, P. Patsalas3, C. Fotakis1,2, E. Kymakis,4, G. Kioseoglou1,5, E. Stratakis1,5 1 Institute of Electronic Structure and Laser (IESL), Foundation for Research and TechnologyHellas (FORTH), Heraklion, 71003, Greece 2 Physics Department, University of Crete, Heraklion, 71003, Greece 3 Physics Department, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece 4 Center of Materials Technology and Photonics & Electrical Engineering Department, Technological Educational Institute (TEI) of Crete, Heraklion, 71003, Greece 5 Materials Science and Technology Department, University of Crete, Heraklion, 71003, Greece iparad@iesl.forth.gr

Owing onolayers of transition metal dichalcogenides (TMDs) are promising new materials for future 2D nanoelectronic systems [1]. With their tunable direct gap in the visible range of the ptical spectrum and high surface-to-volume ratio, these 2D semiconducting systems are ideal for field-effect transistors, photovoltaics, light-emitting diodes (LEDs), single-atom storage, molecule sensing, quantum-state metamaterials and electrocatalytic water splitting applications [2]. Among those unique properties, the outstanding stretchability of 2D crystals is promising for strain engineering and related applications. Indeed, the unprecedented energy levels tunability under strain, predicted for these materials, could lead to "strain-tronic" devices with electronic properties that are controlled via mechanical deformations. For example, single-layer MoS2 is predicted to undergo a direct-to-indirect bandgap transition at ~ 2% of tensile uniaxial strain and a semiconducting-to-metallic transition at 10-15% of tensile biaxial strain[3]. Similar predictions are obtained for WS2 monolayers [4]. Furthermore, phonon softening, valley polarization decrease, and giant valley drift under strain have been reported in MoS2 and WS2 monolayers[5].

Besides this, the boundaries of 2D TMDs crystals are reported to be non-atomically sharp and extremely susceptible to their environment, affecting not only the optical but also their transport properties. Nevertheless, the edge-dependence of the TMDsâ&#x20AC;&#x2122; electronic properties [6], as well as the strain characteristics of the TMDsâ&#x20AC;&#x2122; edges are yet to be explored.

Here we report on the extraordinary strain and photoluminescence (PL) properties, not only of the physical but also of intentionally created via femtosecond laser ablation [7], boundaries of mechanically exfoliated WS2 monolayers. In particular, it is shown that the edges of such monolayers exhibit significant Raman shifts as well as remarkably increased PL efficiency compared to their respective central area. The observed strain varies among the different edges of an individual monolayer and can be compressive or tensile, depending on the mechanical history of the edges during exfoliation (Fig.1). Moreover, there is a 3-fold enhancement of the PL intensity at the edges compared to the monolayer center (Fig.2), with the emission channels being of different origin. Finally, the relation of the observed properties with the chemical nature of the edges is analyzed via Scanning Auger Microscopy (SAM) with high spatial and analysis-depth resolution and discussed accordingly. We envisage that these novel findings could find diverse applications in the development of TMDs-based optoelectronic devices.

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References [1] [2] [3] [4] [5] [6] [7]

D. Akinwande, N. Petrone, and J. Hone, Nat. Commun. 5 (2014) 5678.

F. Bonaccorso, L. Colombo, G. Yu, M. Stoller, V. Tozzini, A. C. Ferrari, R. S. Ruoff, V. Pellegrini, Science, 6217 (2015) 1246501.

E. Scalise, M. Houssa, G. Pourtois, V. Afanasev and A. Stesmans, Nano Res., 5 (2011) 43.

C. H. Chang, X. Fan, S. H. Lin and J. L. Kuo, Phys. Rev. B, 19 (2013) 5420.

C. R. Zhu, G. Wang, B. L. Liu, X. Marie, X. F. Qiao, X. Zhang, X. X. Wu, H. Fan, P. H. Tan, T. Amand, and B. Urbaszek, Phys. Rev. B, 12 (2015) 1301.

H. R. Gutiérrez, N. Perea-López, A. L. Elías, A. Berkdemir, B. Wang, R. Lv, F. López-Urías, V. H. Crespi, H. Terrones and M. Terrones, Nano Lett., 8 (2013) 3447.

I. Paradisanos, E. Kymakis, C. Fotakis, G. Kioseoglou and E. Stratakis, Appl. Phys. Lett., 105 (2014) 041108.

Figures

Figure 1: (a) Optical microscopy image of monolayer and bulk WS 2. Numbers 1 to 10 indicate different areas that was measured by Raman spectroscopy; (b) Raw data of Raman spectra for the 10 different WS2 monolayer areas; (c) Raman shifts of the different areas with respect to the center region of the WS2 monolayer.

Figure 2: (a) Optical microscopy image of bulk and monolayer WS2. (b) Fluorescent image of monolayer. (c) Fluorescent image of monolayer, irradiated and ablated at its lower region by a femtosecond laser pulse. (d) Digitized PL intensity mapping, across the monolayer, following the yellow dashed line of Fig. 2(b). (e) Digitized PL intensity mapping across the laser ablated area, following the blue dashed line of Fig. 2(c).

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Wearable Electronics Using Graphene Hybrid Nanostructures Jang-Ung Park School of Materials Science and Engineering, UNIST, Ulsan 689-798, Korea http://wearable.unist.ac.kr jangung@unist.ac.kr

Wearable electronics is an important area of future electronics. Stretchable and flexible transparent electrodes are required to form wearable displays and touch screen panels with comfort designs. Conductive transparent materials have been intensively studied to replace conventional indium tin oxide (ITO) due to its limited supply and rigidity. Especially, graphene and metal nanowire (NW) random networks have attracted considerable attentions due to their high transparency and conductivity comparable to properties of the ITO electrodes.

Metal nanowire networks can be simply formed through solution processes and have lower sheet resistances than the resistances of undoped synthesized graphene. However, the nanowire networks have critical disadvantages such as high inter-nanowire junction resistances, low breakdown voltages, and high contact resistances with other active materials. Here, we present the formation of the graphene-metal nanowire hybrid films as transparent and flexible electrodes. These hybrid films show low sheet resistance (~30 立/sq), high transmittance (94 % at 550 nm wavelength), and outstanding mechanical stretchability (maximum tensile strain of 100 % with negligible resistance change).

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Conformal and transparent Graphene 3-axis Sensor for artificial skin Minhoon Park, Je jung Kim, Yon-Kyu Park, Jong-Hyun Ahn, Min-Seok Kim School of Electrical and Electronic Engineering Yonsei Universitiy, 50 Yonsei-ro, Seodaemungu Seoul 03722, Republic of Korea Center for Mass and Related Wuantities, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu Daejeon 34113, Republic of Korea minsk@kriss.re.kr, ahnj@yonsei.ac.kr

A considerable amount of research to realize the important issues related to the sensor such as flexibility, stretchablility, multiple functionalities and conformal devices, have been introduced. For showing the multiple functionalities, it is promising to focus on the capability of normal force, shear force detection and the vibration. Especially, there are a variety of papers related to the fingerprint structure which mimic the human skin because of the merit that the fingerprint structure in our human skin have important role such as higher sensitivity and vibration sensing capability. However, adopted sensors which include fingerprint structure by using thick and hard PDMS are not flexible and stretchable. Therefore, it is not suitable for sensor which has higher sensitivity unlike the conformal sensor.[1-3] Additionally, we canâ&#x20AC;&#x2122;t obtain the exact signal without conformal contact which uses the strong adhesion force between substrate and sensor, especially in case of vibration detection. Paper, previously introduced in our group, has better performances of conformal concept such as the strong adhesion force between human skin and sensor than other research. [4] Now, we employed the approach using the conformal graphene 3D sensor which have capability of normal and shear force as well as the vibration detection. Our device effectively determined the direction and roughness even at the frequency which have correlation with the temporal vibration resolution of our human skin. In addition to, we introduced the fancy sensor through bumpless structure. The higher sensitivity, SEM image and vibration data support our concept and introduction. Finally, we showed properties of the various textures sensing including the period and non-period shapes and demonstrated the mini car control applications that explain our concept in this paper.

References [1] [2] [3] [4]

Lucie Viry, Alessandro Levi, Massimo Totaro, Alessio Mondini, Virgilio Mattoli, Barbara Mazzolai, and Lucia Beccai, Advanced Materials, 26 (2014), 2659-2664 Jonghwa Park, Youngoh Lee, Jaehyung Hong, Youngsu Lee, Minjeong Ha, Youngdo Jung, Hyuneui Lim, Sung Youb Kim, and Hyunhyub Ko, ACS Nano, 8 (2014), 1202012029 Jonghwa Park, Youngoh Lee, Jaehyung Hong, Minheong Ha, Young-Do Jung, Hyuneui Lim, Sung Youb Kim, and Hyunhyub Ko, ACS Nano, 8 (2014), 4689-4697 Yong Ju Park, Seoung-Ki Lee, Min-Seok Kim, Hyunmin Kim, and Jong-Hyun Ahn, ACS Nano, 8 (2014), 7655-7662.

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Figures

Figure 1: a. Illustration of conformal graphene 3-axis sensor, calculated adhesion energy of the sensor as a function of the substrateâ&#x20AC;&#x2122;s thickness and SEM image b. Photographes of a conformal 3axis sensor. c. Illustration of operation principle related to the normal force, shear force and vibration.

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2-Dimensional Layered Materials for Si Technology Seongjun Park Device & System Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, 130 Samsung-ro, Yeongtong-gu, Suwon, Gyeonggi-do, 16678, Republic of Korea S3.Park@Samsung.com

Two dimensional (2D) materials are crystalline materials with layered structures, including Graphene, h-BN, and Transition Metal Di-chalcogenides (TMD's). Each of their layers is consisting of one or a few atomic layers and they form van der Waals interactions with neighboring layers. Recently, they have been studied intensively due to their extraordinary properties, such as, flexibility and transparency. In addition, they have exceptional electronic, optoelectronic, chemical and mechanical properties. For example, Graphene has high electron mobility, chemical inertness, and thermal conductivity, while TMD has high photo responsivity. Based on their properties, many potential applications were proposed and demonstrated.

We have been investigated 2D layered materials for Si technology. We have focused 2D layered materials as interface materials due to the chemical inertness and their atomically thin nature. Especially, Graphene has been suggested as a promising material for future interconnects between devices because of its unique electrical and chemical properties. For instance, they are good candidates for diffusion barrier.[1] Also, they are good candidates for interface materials between metal and Si to reduce the Schottky barrier heights and contact resistance in source and drain, which is one of the most critical issues for scaling down.[2].

In this talk, we will cover and discuss the possibility of Graphene and other 2D layered materials for interconnects and contact resistance reducer in Si technology. In addition, we will also cover other potential applications based on 2D materials' unique properties, such as, chemical inertness and atomic thick nature.

References [1] [2]

L.Li et al., ACS Nano, 9 (2015) pp. 8361-8367.

K.-E. Byun et al., Nano Letters, 13 (2013) pp. 4001-4005.

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A graphene touch panel display: The mechanical effect J. Parthenios1, G.Anagnostopoulos1, P. Pappas1, Z. Li2, I. A. Kinloch2, R. J. Young2, K. S. Novoselov3, C. Y. Lu4, N. Pugno5, C. Galiotis1,6 and K. Papagelis1,7 1 FORTH/ ICE-HT, Patras 265 04, Greece 2 School of Materials, University of Manchester, Manchester, UK 3 School of Physics and Astronomy, University of Manchester, Manchester, UK 4 BGT Materials Limited, 2.312 Photon Science Institute, University of Manchester, Manchester, UK 5 Laboratory of Bio-Inspired and Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy 6 Department of Chemical Engineering, University of Patras, Patras GR-26504, Greece 7 Department of Materials Science, University of Patras, Patras GR-26504, Greece jparthen@iceht.forth.gr

Polymer based touch panel displays using transparent conductive films from carbon nanotubes and graphene are considered as key components in new-age optoelectronics such as in flexible, stretchable and wearable devices [1]. In touch panels, the forces exercised by the operator’s finger or commercial styluses transmit bending stresses, as well as dynamic contact stresses during lifetime operation. In this work, the mechanical performance of a prototype graphene based touch panel display is investigated (a) under quasi static tensile loading conditions and (b) under dynamic loading at various frequencies and temperature ranges. The display (fig. 1a) consisted of two individual layers of CVD graphene embedded into PET films and supplied by BGT Materials.

It has been found [2], that the deposition of CVD graphene onto PET films results in a specific wrinkling pattern, where wrinkles form individual domains (“islands”) of flat graphene. The role of this pattern on the mechanism of stress transfer in the examined touch panel display is investigated by means of Raman spectroscopy [3] (fig.1b). Thermo-mechanical tests resembling real-life operation in terms of frequency and temperature revealed that the display is mechanically robust. The outcome of this work may have important implications in the fabrication of next generation flexible touch panel displays.

References [1] [2] [3]

Du, J.; Pei, S.; Ma, L.; Cheng, H. M., Advanced Materials 26(13) 2014, 1958-1991.

Li, Z.; Kinloch, I. A.; Young, R. J.; Novoselov, K. S.; Anagnostopoulos, G.; Parthenios, J.; Galiotis, C.; Papagelis, K.; Lu, C.-Y.; Britnell, L., Acs Nano 9(4) 2015, 3917-3925.

Anagnostopoulos, G.; Androulidakis, C.; Koukaras, E. N.; Tsoukleri, G.; Polyzos, I.; Parthenios, J.; Papagelis, K.; Galiotis, C., Appl Materials & Interfaces 7(7) 2015, 42164223.

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Figures

(a)

(b) (c)

Figure 1: (a) A prototype graphene based display, (b) Pos(2D) as a function of uniaxial strain for two deformation cycles in quasi static tensile tests, and (c) Simulating the stylus force in a dynamic loading test.

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Strain engineering of thermal transport in twodimensional grain boundaries Alessandro Pecchia1, Leonardo Medrano Sandonas*2,3, Rafael Gutierrez2, Gotthard Seifert4, and Gianaurelio Cuniberti2,5,6 1 Consiglio Nazionale delle Ricerche, ISMN, Via Salaria km 29.6, 00017 Monterotondo, Rome, Italy 2 Institute for Materials Science, TU Dresden, 01062 Dresden, Germany 3 Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany 4 Physical Chemistry Department, TU Dresden, 01062 Dresden, Germany 5 Center for Advancing Electronics Dresden, TU Dresden, 01062 Dresden, Germany 6 Dresden Center for Computational Materials Science, TU Dresden, 01062 Dresden, Germany alessandro.pecchia@ismn.cnr.it

Grain boundaries (GBs) in two-dimensional materials have attracted great attention in recent years due to its unique physical properties [1]. However, many questions are still unanswered about the influence of external factors on their thermal properties. In a previous work, we have shown that functionalization plays an important role in the thermoelectric properties of graphene grain boundaries [2]. Now, we want to provide some insights in understanding the influence of strain on the thermal transport properties of novel two-dimensional materials with grain boundaries. To do this, we employ equilibrium Greenâ&#x20AC;&#x2122;s Functions technique combined with density functional tight-binding (DFTB) theory [3]. Our main focuses are grain boundaries in hBN, Phosphorene, and MoS2 monolayers; which are potential candidates for developing novel approaches to nanoscale electronics and phononics. Among the GBs studied in the present work (5|7 and 4|8), 4|8 GB has the stronger influence on the thermal transport. We have also found an anomalous behavior of the thermal conductance after increasing the uniaxial strain, which can be tuned by considering temperature effects in the grain boundary. This trend is associated to the strain and temperature dependences of the bond length and the force constants of the material. Thus, our result opens up the possibility of controlling the thermal conductance by setting a specific configuration for the experiments.

Hence, it is an open question of how strain affects the properties of heterostructures built of graphene and other 2D materials, which will allow novel properties and applications to be explored. It is expected that strain engineering may also shed light to design new type of electronic and phononic devices [4].

References [1] [2] [3] [4]

Oleg V. Yazyev and Yong P. Chen, Nature Nanotechnology, 9 (2014) 755-767.

L. Medrano Sandonas, R. Gutierrez, A. Pecchia, A. Dianat, and G. Cuniberti, Journal of Self-Assembly and Molecular Electronics, 3 (2015) 1-20.

A. Pecchia, G. Penazzi, L. Salvucci, and A. Di Carlo, New Journal of Physics, 10 (2008) 065022.

D. Akinwande, N. Petrone, and J. Hone, Nature Communications, 5 (2014) 5678.

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Figures

Figure 1: Schematic representations of the grain boundaries (GBs) studied in the present work.

Figure 2: Strain dependence of the thermal conductance for hexagonal boron-nitride 4|8 GB.

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New two-dimensional crystals: controlled synthesis and optoelectronic devices Hailin Peng Center for Nanochemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China hlpeng@pku.edu.cn

The unique structure and properties of two-dimensional (2D) crystals have a large impact on fundamental research as well as applications in electronics, photonics, optoelectronics and energy sciences. Here our recent studies on the controlled synthesis of new 2D crystals such as topological insulator V2VI3 nanostructures, other layered metal chalcogenides and their hybrid materials, as well as their optoelectronic properties will be discussed. We propose a method combined with micro-contact printing growth and van der Waals epitaxy to achieve the controlled growth of various 2D crystal arrays with well-aligned orientation, controlled thickness, and specific placement, which can be used for efficient photodetection applications. Our studies suggest that functional 2D crystals hold great promise for future electronic and optoelectronic applications.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Peng, H.; et al., Nature Materials 2010, 9: 225.

Peng, H.; et al., Nature Chemistry 2012, 4: 281.

Li, H.; Peng, H.; et al., J. Am. Chem. Soc. 2012, 134: 6132.

Lin M.; Peng H.; et al., J. Am. Chem. Soc. 2013, 135: 13274 Guo Y.; Peng H.; et al., Adv. Mater. 2013, 25: 5959 Zhou, Y.; Peng, H.; et al., ACS Nano 2014, 8: 1485 Zheng, W.; Peng, H.; et al., Nature Comm. 2015, 6: 6972.

Zhou, W.; Wu, S.; Peng, H.; Liu, K.; et al., J. Am. Chem. Soc. 2015, 137: 7994.

Deng, B.; Hsu, P.; Cui, Y.; Liu, Z.; Peng. H.; et al., Nano Lett. 2015, 15, 4206.

Zhang, C.; Peng, H.; Z. Liu, Z.; et al., Nature Comm. 2015, 6, 6519.

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Additive Free, Single Layer Graphene in Water Alain Pénicaud1 , George Bepete1, Eric Anglaret2, Luca ortolani3, Vittorio Morandi3 and Carlos Drummond1 1 Centre de recherche Paul Pascal – CNRS, Université de Bordeaux, France 2 Laboratoire Charles Coulomb, Université de Montpellier – CNRS, France 3 CNR IMM-Bologna, Via Gobetti 101, 40129 Bologna, Italy penicaud@crpp-bordeaux.cnrs.fr

Full exfoliation of graphite to form thermodynamically stable, negatively charged, graphene (graphenide) flakes in solution can be achieved by dissolution of graphite intercalation compounds (GICs) in low boiling point aprotic organic solvents under inert atmosphere[1,2].

We now report that, under certain conditions, graphenide can be transferred to water as single layer graphene. The organic solvent can then be evaporated to remain with an aqueous graphene suspension of ca 0.15 mg/ml concentration under ambient atmosphere.

The Raman spectra (2.33 eV laser) collected in situ on such dispersions show bands at 1343, 1586, 1620 and 2681 cm-1 corresponding to the D, G, D’ and 2D bands of graphene respectively. The 2D band at 2681 cm-1 is well fitted with a sharp lorentzian line (∼28 cm-1) which is a hallmark of single layer graphene [3]. We have thus succeeded in preparing air stable, bulk suspensions of single layer graphene in water [4].

References [1] [2] [3] [4]

A. Catheline et al. Soft Matter, 12, 7882, (2012) A. Pénicaud & C. Drummond, Acc. Chem. Res. 46, 129 (2013) Y.Y. Wang et al. J. Phys. Chem. C., 112(29), 10637, (2008).

G. Bepete, C. Drummond, A. Pénicaud, European patent, June 12, 2014, EP14172164.

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Graphene materials for energy and composites applications Julio Gomez Cordon, Javier Perez AVANZARE, Avda Lentiscares 4-6, Navarrete, Spain julio@avanzare.es

The bulk graphene market, will exponentially grow in the next few years. Their application in composites will be the largest segment, followed by energy storage applications. [1] Different synthetic methods can be use for the production of graphene and graphene related materials. [2] However most of the materials labeled as graphene in the market, are far from the classification and nomenclature for Graphene-Based Materials[3] and this heck of a lot of production capacity, specially of nanographite materials in factories but lacks a killer app.

[1c] Several reviews analyzed the applications of the different graphene and related products in energy [4, 1b] and in composites applications. [5, 1b] In this communication, 3 different methods for the production of bulk graphene or reduce graphene oxide: liquid exfoliation, reduced graphene oxides and high expansion were compared with other production methods and products in the market. The complete characterization of graphene and highly reduce graphene oxide using TEM, SEM, AFM, XPS, DRX, Laser diffraction, surface area analysis, etc will be presented.

The use of graphene materials and decorated graphene materials in energy applications from batteries to supercapacitors with ultrahigh energy density will be also presented.

Different types of graphene materials with variation in lateral size, defects and defects concentration, thickness,, etc, have been used to obtain the graphene-thermoplastic and thermoset composites. The different effect of the incorporation of liquid exfoliated graphene, highly reduced graphene oxide and graphene nanoplatelets on the electrical, thermal conductivity and fire retardant properties of epoxy were investigated.

Related to electrical properties, some of this composites show lower percolation threshold limits than the previously reported values,[6] also obtaining ultralow percolation limits, opening a new range of applications and markets.

Other factors as processing technique, the compatibility between graphene and matrix and dispersion have an extremely high importance in the results

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References [1] [2] [3] [4] [5] [6]

a) Zh Ma, R. Kozarsky, M. Holman., GRAPHENE MARKET UPDATE. LUX RESEARCH (2014). b) Ferrari A Cet al Nanoscale 7 (2015) 4598–810, c) M. Peplow, Nature 522, (2015), 268 W. Ren, H.-M. Cheng, Nature Nanotechnology 9, (2014) 726–730 P. Wick et all, Angew. Chem. Int. Ed. 53 (2014)7714–7718. b) R. Hurt et all, Carbon, 65 (2013) 1-6 The role of graphene for electrochemical energy storage. Nature Materials 14 (2015) 271–279. a) P Samorì, I A Kinloch, X Feng and V Palermo, 2D Mater. 2 (2015) 030205 b) R. J. Young, I. A. Kinloch, L. G., Kosty. S. Novoselov, Composites Science and Technology, 72 (2012) 1459–1476.

Galindo B, Gil Alcolea S, Gómez J, Navas A, Ortega Murguialday A, Pérez Fernandez M, Puelles R C 2014 IOP Conf. Ser.: Mater. Sci. Eng. 64 012008.

Figures

Figure 1: sp2/sp3 ratio and Pore volume vs BET for some of the RGO prepared.

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Resonance Raman spectroscopy in novel 2D structures Marcos A. Pimenta Departamento de Física, UFMG, Brazil

The discovery of graphene opened the new area of study about two-dimensional (2D) materials. It was observed that the physical properties were different in structures with more than one atomic layer, and also dependent on the twisting angle between two layers. New types of 2D structures emerged as very promising materials, such as the transition metal dichalgogenides (TMDs), which can exhibit a semiconductor or metallic behavior depending on the type of atoms. More recently, black phosphorus attracted the attention of many scientists, because it is also a mono-atomic 2D structure, such as graphene, but many of its properties are anisotropic in the 2D plane, and strongly dependent on the number of layers.

Resonance Raman spectroscopy (RRS) has shown to be a very useful tool to provide information about the interaction of phonons with electrons or excitons in different 2D materials. We will present RRS results in different 2D structures, starting from the discussion of the effect on the Raman spectra of the twisting angle between two graphene layers, in a bilayer structure. We will show that new peaks appear in the Raman spectra of twisted bilayer graphene, and that they can have different physical origin. The anomalous enhancement of the G band is observed when the laser excitation energy is in resonance with the van Hove singularities, which are generated by the Moire superstructure [1]. We will then present a RRS study of different samples of 2D transition metal dichalcogenides (MoS2, WS2 and WSe2) with one, two and three layers (1L, 2L, 3L) and bulk samples, using dozens of different laser excitation lines covering the visible range [2-4]. We observed that all Raman features are enhanced by resonances with excitonic transitions, and from the laser energy dependence of the Raman excitation profile (REP) we obtained the energies of the excitonic states and their dependence with the number of atomic layers. In the case of MoS2, we observed that the electron-phonon coupling is symmetry-dependent, and our results provide experimental evidence of the C exciton recently predicted theoretically [4].

Finally, we will present a polarized Raman study about black phosphorus, by changing the polarization of the incident and scattered beam with respect to the crystalline axes. We observed an unusual angular dependence of the polarized spectra, which could only be explained by taking into account the complex values of the Raman tensor elements [5].

References [1] [2] [3] [4] [5]

H.B. Ribeiro, Carbon vol. 90, 138-145 (2015) E. del Corro, ACS Nano, 8 (9), pp 9629–9635 (2014) M. A. Pimenta, , Accounts of Chemical Research Vol. 48 pp 41–47 (2014) B R Carvalho, Phys Rev. Letters vol. 114, 136403 (2015) H. B. Ribeiro, ACS Nano, vol. 9, 4270 (2015)

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Non equilibrium optical properties of monolayer MoS2 probed by ultrafast spectroscopy E.A.A. Pogna1, S. Dal Conte1, F. Bottegoni1, M. Marsili2, D. Sangalli3, D. De Fazio4, D. Yoon4, A. Lombardo4, M. Bruna4, I. Bargigia5, C. D’Andrea5, C. Manzoni1, F. Ciccacci1, A. Marini3, D. Prezzi2, M. Finazzi1, A.C. Ferrari4 and G. Cerullo1 1 Politecnico di Milano, 32 p.zza Leonardo da Vinci, I-20133 Milano, Italy 2 CNR-Istituto Nanoscienze, I-41125 Modena, Italy 3 CNR-Istituto di Struttura della Materia, Montelibretti, Italy 4 Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 OFA, UK 5 Center for Nano Science and Technology at PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli, 70/3Milan, Italy eva.a.pogna@gmail.com

In layered semiconductors, such as transition metal dichalcogenides (TMD), the electronelectron interaction is strongly enhanced by both quantum confinement and reduced screening [1]. Furthermore, in these materials the valley polarization can be optically controlled by means of circular polarized light [2]. We investigate single-layer MoS2 (1L-MoS2) with ultrafast transient absorption spectroscopy (Fig.1a) and time resolved ab-initio simulations [3] based on the non-equilibrium Green's functions and density-functional theory [4]. This comparison indicates that the non-equilibrium optical properties of TMDs are influenced by the renormalisation of both band gap and exciton binding energies caused by photo-excited charge carriers. The exciton valley relaxation dynamics [5] is investigated by time-resolved Faraday rotation. A circularly polarized pump pulse creates a spin and valley polarized population in the conduction/valence band, which causes the rotation of the linear polarization of a delayed probe pulse. The probe pulse energy is tuned below the absorption gap to be sensitive only to the helicity-dependent light scattering of the photoexcited electrons and holes. Since probe photons couple to the charge carriers orbital momentum, which in 1L-MoS2 is locked to the valley index, the rotation angleF probes the intervalley relaxation processes. We observe a double exponential decay (Fig.1b), with an initial fast (~200fs) decay due to scattering of spin-polarized excitons from K to K’. This is in good agreement with the time scale predicted by the Maialle-Silva-Sham electron/hole exchange interaction mechanism, which can be interpreted as a virtual annihilation of a bright exciton in one valley followed by the creation of an exciton in the opposite valley.

References [1] [2] [3] [4] [5]

Qiu, D. Y. et al.Phys. Rev. Lett., 111 (2013) 216805.

Jones, A. M. et al. Nat. Nanotechnol., 8 (2013) 634−638.

Eva A. A. Pogna et al., ACS Nano, 10 (2016) 1182–1188.

Marini, A.; Hogan, C.; Gruning, M.; Varsano, D. Comput. Phys. Commun., 180 (2009) 1392.

S. Dal Conte et al., Phys. Rev. B, 92 (2015) 235425.

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Figures

Figure 1: Non equilibrium optical properties of 1L-MoS2. (a) Transient absorption spectra (A) at different excitation energies (pump); (b) Time-resolved Faraday rotation (F).

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A convenient quantum Hall resistance standard in graphene devices: performance and physics W. Poirier1, J. Brun-Picard1, R. Ribeiro-Palau1, F. Lafont1, D. Kazazis2 , A. Michon3 , O. Couturaud4 , C. Consejo4, B. Jouault4, F. Schopfer1 1 Laboratoire National de Métrologie et d’Essais, Trappes, 78190, France 2 Laboratoire de Photonique et Nanostructures, CNRS, Marcoussis, 91460, France 3 3Centre de Recherche sur l’Hétéroépitaxie et ses Applications, CNRS, Valbonne, 06560, France 4 Laboratoire Charles Coulomb, Université de Montpellier 2, CNRS, Montpellier, 34095, France wilfrid.poirier@lne.fr

An ongoing goal of metrologists is to exploit the robustness of the quantum Hall effect in graphene to develop quantum Hall resistance standards (QHRS) operating in more convenient experimental conditions than the usual standards made of GaAs/AlGaAs heterostructures, which require high magnetic inductions (B~10T), low temperatures (T~1.3 K) and currents (I~40 µA) to be accurate to within 10-9 , in relative value. Indeed, making QHRS compatible with simple cryogen-free experimental setups would improve the dissemination of an accurate realization of the ohm. Although the 10-9 accuracy of the quantized Hall resistance RH on the =2 plateau ( is the Landau level filling factor) was demonstrated in a few graphene devices [1], this was obtained at still high and not competitive operating magnetic fields up to now.

We will present measurements performed in Hall bar devices, made of graphene grown by chemical vapor deposition (CVD) of propane/hydrogen on SiC, that can demonstrate quantization of RH within 1x10-9 under relaxed and extended experimental conditions. Figure 1a reports the Hall RH and longitudinal Rxx resistances as a function of B measured in a graphene device with electron density of 1.8x1011 cm-2 and mobility of 9400 cm2 V -1 s -1 . It shows a RH plateau extending from 2.5 T to 14 T, much wider that the one of a GaAs/AlGaAs reference device. By comparison with a GaAs/AlGaAs QHRS, RH in this graphene device was found accurately quantized within 1x10-9 (or below) over a 10-T wide range of B with a remarkable lower bound at 3.5 T (fig.1b), T as high as 10 K, or I as high as 0.5 mA. The quantization accuracy was even tested within the ultimate measurement uncertainty of 8.2x10-11. The (B, T, I) parameter space ensuring a 1x10-9 quantization accuracy of RH is found much extended in this graphene device than in the GaAs-based device. This makes this graphene QHRS versatile since it can be used in various combinations of experimental conditions [2]. This performance is explained by a strong localization of the electronic states in the bulk which maintains over a wide range of parameters, as revealed by the measurement of Rxx values as low as a few µ  (fig.1c). Variable range hopping mechanism with soft Coulomb gap can explain the evolution of Rxx as a function of T and I, over a wide range of B, in the samples of intermediate electron density ( 3.2x1011 cm-2) [3]. Besides, in the lowest carrier density sample, this dissipation mechanism model is questioned. All these features, as well as the coupling between RH and Rxx, will be discussed considering the device structural properties.

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References [1] [2] [3]

T. J. B. M Janssen et al, Rep. Prog. Phys. 76, 104501 (2013).

R. Ribeiro-Palau et al, Nature Nanotech.10, 965 (2015).

F. Lafont et al, Nature Commun. 5, 6806, (2015).

Figures

Figure 1: a) RH and Rxx versus B; b) Relative deviation of RH measured in graphene from RH measured in GaAs/AlGaAs versus B; c) Rxx in graphene versus B, for several I values.

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Current-driven non-reciprocal plasmons in graphene Marco Polini Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, I-16163, Genova, Italy Marco.Polini@iit.it

Realizing surface plasmon polariton modes with long lifetimes is the biggest challenge of contemporary plasmonics. Graphene sheets encapsulated between boron nitride crystals, which currently have the highest room-temperature dc mobility in the realm of twodimensional materials [1], display amazingly long Plasmon lifetimes in the mid-infrared spectral range, approaching 1 ps [2]. Unfortunately, this is not yet enough for applications where vectoring confined optical signals over long distances is required (i.e. optical interconnects). In this talk, I will discuss a recent theoretical proposal [3] where a fundamental materials science aspect of graphene, i.e. its capability to withstand large dc currents without burning [4], is utilized for achieving plasmon non-reciprocity and collimation. I will present extensive calculations of the plasmonic properties of a graphene sheet carrying a dc current. By employing a suitable random phase approximation, which is non-perturbative in the ratio between the drift velocity and the graphene Fermi velocity, I will demonstrate that graphene plasmons in the presence of a dc current display non-reciprocity and collimation.

References [1] [2] [3] [4]

See, for example, D.A. Bandurin, I. Torre, et al., Science (February 11, 2016; DOI: 10.1126/science.aad0201) and arXiv:1509.04165.

A. Woessner, M.B. Lundeberg, et al., Nature Mater. 14, 421 (2015).

B. Van Duppen, A. Tomadin, et al., 2D Mater. 3, 015011 (2016).

J. Moser, A. Barreiro, and A. Bachtold, Appl. Phys. Lett. 91, 163513 (2007).

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Next Generation of Nano-Enhanced Composites and 3D Printable Materials Elena Polyakova Graphene 3D Lab, USA

The 3D printing market is expected to grow quickly over the course of the next few years, without factoring in the likelihood of advances in both printer and filament technologies.

Nano-composites are actively used in production of advanced filaments. As an example, adding graphene filler to filaments increases the strength and adds conductivity to endproducts made via 3D printingâ&#x20AC;&#x201C; a major advancement when considering using 3D printing for energy storage, electronic, and other commercial applications. Dr. Polyakova will overview the recent progress made in this area at Graphene 3D Lab and its long-term effects on the 3D printing industry.

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N-doped Mesoporous Molybdenum Disulfide Nanosheets: Synthesis and Application in Lithium Ion Batteries Si Qin, Weiwei Lei, Dan Liu, and Ying Chen Institute for Frontier Materials, Deakin University, 75 Pigdons Rd, Waurn Ponds, Victoria 3216, Australia siq@deakin.edu.au

Molybdenum disulfide (MoS2) nanosheet has unique physical and chemical properties, which make it a promising candidate for next generation electronic and energy storage applications. Two-dimensional MoS2 nanosheets can be feasibly synthesized by a simple, effective and large-scale approach. MoS2 nanosheets synthesised by this method show a porous structure formed by curled and overlapped nanosheets with well-defined edges.

Analysis of the nanosheets shows that they have an enlarged interlayer distance and high specific surface. X-ray photoelectron spectroscopy analysis shows the nanosheets have MoN bond indicating successful nitrogen doping. The nitrogen content of the product can be modulated by adjusting the ratio of starting materials easily with within the range from ca. 5.8 to 7.6 at%.

MoS2 as anode material in lithium ion battery usually suffers from poor cycling stability and low rate capability. N-doped MoS2 nanosheets show enhanced lithium storage performance, delivering a high reversible specific capacity, rate performance, coulombic efficiency, and cycling stability compared with particles and non-doped nanosheets. The discharge capacity of 998.0 mAh g−1 at 50 mA g−1 after 100 cycles, and 610 mAh g−1 at a rate of 2 A g−1 can be achieved with their better electrical and ionic conductivity, improved lithium ion diffusion and lower polarization. The excellent lithium storage performance of the MoS2 nanosheets can be attributed to their large surface area, layered and porous structure, increased interlayer distance, and high concentration N doping.

References [1] [2]

Si Qin, Weiwei Lei, Dan Liu, Ying Chen, Scientific Reports, 4 (2014) 7582.

S Si Qin, Weiwei Lei, Dan Liu, Ying Chen, J. Mater. Chem. A, 3 (2015) 18238-18243.

Figures

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Fabrication of Smart Systems on Flexible Substrates Enabled by Graphene Integration S.Ravesi1, S.Abbisso1, S. Di Marco1, G. Fisichella2, F.Giannazzo2, S. Lo Verso1, S.Smerzi1, V.Vinciguerra1 1 STMicroelectronics, ADG R&D, Stradale Primosole 50, 95121 Catania, Italy 2 CNR-IMM, Strada VIII, 5, 95121 Catania, Italy sebastiano.ravesi@st.com

The marvelous chemical and physical properties of graphene make it as an ideal candidate to enable the fabrication of new electronic devices, especially in the realm on More than Moore [1]. Among its properties the mechanical and electronics ones could be exploited for the development of integrated smart systems on flexible substrates to be used on IoT and wearable electronics applications.

In the framework of EC funded Graphene Flagship, together with our partners, we have demonstrated the feasibility of a sensor node in which many of the system functions can benefit from the grapheme use [2]. Graphene based sensors have been developed, and graphene based material has been used for antennas, for communication and energy harvesting, and batteries for energy storage, while the high level functions, signal processing and radio chip, have been delegated to standard Si based technology.

This hybrid approach, mixed graphene and Si based technologies, has been adopted at lower level also for manufacturing approach for the graphene components, and different techniques have been adopted: printing, lithography, graphene ink, CVD graphene and so on.

In this paper weâ&#x20AC;&#x2122;ll focus on wafer scale processing of graphene based components in a CMOS 6â&#x20AC;? fab environment, going through the main technological challenges that have to be tackled in order to fabricate the demonstrator onto a large area flexible substrate. The transfer of CVD monolayer graphene on plastic substrates has been largely investigated, taking in account three major constraints: to have high quality graphene transferred on a large area; to minimize the risk of cross contamination (metal residuals and/or organic solvents) [3]; the presence of steps and morphology related to the previous device architecture. The optimization of processing flow of G-FET as elementary brick of the technological platform will be presented, with focus on the interaction between graphene and the other device materials and on the constraints dictated by the plastic substrate.

References [1] [2] [3]

A.C.Ferrari et al., Nanoscale 10 (2014) 1039.

This research was supported by European Union Seventh Framework Programme under Grant Agreement No. 604391 Graphene Flagship.

G.Fisichella et al., Applied Physics Letters, 104 (2014) 233105.

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From Graphene to 2D Transition Metal Carbides: Synthesis and Applications Wencai Ren Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P.R. China wcren@imr.ac.cn

Two-dimensional (2D) materials show many fascinating properties, however, different 2D materials are required for different applications. The controlled synthesis and applications of graphene materials will be first discussed, including chemical vapor deposition (CVD) growth of large-area high-quality graphene single crystals, films and their applications in flexible touch panels and OLEDs [1-3], large-scale production of highly conductive pristine graphene nanosheets by intercalation-exfoliation method and their applications in lithium ion batteries (LIBs), lithium sulfur batteries, anti-corrosion coatings, and thermal management, [1,4-7], and CVD growth of highly conductive flexible three-dimensional graphene network structures and their applications in elastic conductors, flexible LIBs with ultrafast charge and discharge rates, lightweight and flexible electromagnetic interference shielding materials, and flexible high-energy lithium sulfur batteries [8-12].

In addition to graphene, we have realized the self-limited catalytic surface growth of uniform millimetre-sized monolayer WS2 single crystals and large-area continuous films by ambientpressure CVD on flexible Au, and developed a low-cost roll-to-roll/bubbling method for production of large-area flexible films of monolayer, double-layer WS2 and WS2/graphene heterostructures, and batch fabrication of flexible monolayer WS2 film transistor arrays [13].

We also developed a CVD method, with a bilayer of a Cu foil sitting on a transition metal foil as the substrate at a temperature above the melting point of Cu, to grow large-size highquality ultrathin 2D transition metal carbide (TMC) crystals such as Mo2C, WC, and TaC14. For instance, the 2D Îą-Mo2C crystals obtained are a few nanometers thick, over 100 ď ­m in lateral size, very stable under ambient conditions, and show 2D superconductivity14. These ultrathin TMC crystals further expand the large family of 2D materials.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

W.C. Ren, H.M. Cheng, Nature Nanotechnology 9 (2014) 726.

L.B. Gao, W.C. Ren, H.M. Cheng, et al., Nature Communications 3 (2012) 699.

T. Ma, W.C. Ren, H.M. Cheng, et al., PNAS 110 (2013) 20386.

S.F. Pei, W.C. Ren, H.M. Cheng et al., Chinese Patent 201110282370.5.

G.M. Zhou, S.F. Pei, F. Li, H.M. Cheng, et al., Advanced Materials 26 (2014) 625.

G.M. Zhou, F. Li, S.F. Pei, H.M. Cheng, et al., Advanced Materials 27 (2015) 641.

L. Chen, W.C. Ren, et al., Advanced Materials 28 (2016) 510.

Z.P. Chen, W.C. Ren, H.M. Cheng, et al., Nature Materials 10 (2011) 424.

N. Li, W.C. Ren, F. Li, H.M. Cheng, et al., PNAS 109 (2012) 17360.

Z. P. Chen, W. C. Ren, H. M. Cheng, et al., Advanced Materials 25 (2013) 1296.

G.M. Zhou, F. Li, W.C. Ren, H.M. Cheng, et al., Nano Energy 11 (2015) 356.

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[12] G.J. Hu, C. Xu, W.C. Ren, et al., Advanced Materials 10.1002/adma.201504765.

[13] Y. Gao, W.C. Ren, et al., Nature Communications 6 (2015) 8569.

[14] C. Xu, W.C. Ren, et al., Nature Materials 14 (2015) 1135.

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Graphene Protein Microfluidic FET Sensors V. Renugopalakrishnan Boston Childrenâ&#x20AC;&#x2122;s Hospital, Harvard Medical School and Northeastern University, Boston, MA 02115, USA

Chronic diseases are becoming more prevalent, and the complexities of managing patients continue to escalate since their care must be balanced between the home and the clinical settings. Diabetes is the most advanced example where self-monitoring has been shown to be necessary. Glucometers are point-of-care (POC) devices that have become standard at home and clinical settings. Similarly, many other POC biosensors have also been developed.

Enzymes are often used in these sensors because of their specificity and the reaction products can be electrochemically transduced for the measurement. When enzymes are immobilized to an electronically active substrate, the enzymatic reactions can be transduced by direct electron transport. This paper describes an approach for the development of graphene-based POC devices. This includes modifying enzymes for improved performance, developing methods to bind them to the graphene surface, incorporation of the functionalized graphene on a field-effect transistor (FET), and integration into a microfluidic device suitable for home use. This paper describes an approach for the development of a graphenebased POC biosensor platform using glucose as an example of target molecule. We are also focusing on micro RNA, triglycerides, ammonia in plasma. The sensitivity levels observed confirm that the analytes of blood can be detected upto picomolar levels.

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Metrology for graphene, and graphene for metrology Curt A. Richter NanoElectronics Group, Engineering Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA Curt.Richter@NIST.gov

The measurement infrastructure for graphene and related two-dimensional (2D) materials must be improved and focused in order for the technological promise of these materials to come to fruition. The comparison of the results of a suite of analytical measurements with the results of electrical test structure and device measurements to directly determine the relationship between the underlying atomic and chemical structure of the materials and interfaces and the end electrical device behavior is a powerful method to research and development. Such data on the structure-function relationship can be used to guide the optimization of device structures and fabrication processes. For example, by combining the results of a sophisticated suite of measurements (Raman spectroscopy, photoemission spectroscopy, scanning electron microscopy, and atomic force microscopy) with the electrical device parameters obtained from well-designed test structures, processes for metal contacts to 2D materials such as graphene [1] and molybdenum-disulfide (MoS2), [2] are improved leading to higher performance electronic devices. The fundamental optical properties of 2D materials (e.g. archival data) must be carefully measured to enable optical methods such as Raman spectroscopy and spectroscopic ellipsometry to be used for determining material quality and process monitoring.

The unique physical and electrical properties of graphene also can be harnessed to improve measurements of other materials and systems. For example, by using an optically transparent grapheme contact in internal photoemission (IPE) measurements, the offsets of both the valance band and the conduction band at the buried heterojunction interface of a InAs/GaSb tunnel field-effect transistor can be experimentally extracted. [3] This information is critical to optimize the electronic performance of these emerging nanoelectronic devices. In addition, graphene-based devices can be directly used to provide fundamental metrology for traceable standards. Due to its energetics, graphene allows observation of the quantum Hall effect at higher temperatures and lower magnetic fields then in traditional GaAs-based devices. With controlled device engineering of graphene p/n junctions a wide and tunable range of quantized resistance values can be observed at a fixed magnetic field. [4].

References [3] [4] [5] [6]

Wei Li, et al., J. Appl. Phys. 115, http://dx.doi.org/10.1063/1.4868897 2014) 114304.

Hui Yuan, et al., ACS Appl. Mater. Inter. 7 (2), DOI: 10.1021/am506921y (2015) 1180.

Wei Li, et al., Appl. Phys. Lett. 105 (2014) 213501.

Nikolai N. Klimov, Son T. Le, et al., Phys. Rev B, 92, (2015) 241301(R).

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Figures

Figure 1: Correlation of the results of electrical device parameterization with Raman spectra to improve metal/MoS2 contacts.

Figure 2: Multiple quantize resistance values observed in a graphene p/n junction Hall bar device.

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Experimental and theoretical investigation of highly tunable graphene-GaSe field-effect devices with dual heterojunction Juha Riikonen1 *, W. Kim1 , F. A. Chaves2, D. Jiménez2, R. D. Rodriguez3, J. Susoma1, M. A. Fenner4, C. Li1, and H. Lipsanen1 1 Aalto University, Department of Micro and Nanosciences, P.O.Box 13500, Espoo, Finland 2 Departament d'Enginyeria Electrònica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain 3 Technische Universität Chemnitz, Institut für Physik, Reichenhainer Str. 70, 09126 Chemnitz, Germany 4 Keysight Technologies, Lyoner Strasse 20, 60528 Frankfurt, Germany juha.riikonen@aalto.fi

Graphene transistors have recently surpassed the gigahertz limit and are expected to impact next generation radio frequency electronics. However, the performance of graphene transistors as logic components is limited by the zero bandgap. Therefore, variety of different semiconducting 2D materials have been under intense investigation. Recently, van der Waals heterojunctions between graphene and other 2D materials have also received significant attention.

Among the binary chalcogenides MoS2 is probably the most widely investigated material.

Very limited number of studies has examined GaSe although it is also a layered 2D semiconductor. Bulk GaSe is a known nonlinear material in photonics and it has a direct bandgap in the visible range (2.1 eV, 590 nm) regardless of the thickness whereas MoS2 has a direct bandgap only in monolayer form. GaSe forms planar tetra-layer (TL) structures and one TL consists of four covalently bonded stacks in a sequence of Se–Ga–Ga–Se. Exploiting these benefits, we have recently reported on the nonlinear optical properties of GaSe by investigating second and third harmonic generation [1] using multiphoton microscopy [2].

In this work, we demonstrate highly tunable transport characteristics of a graphene–GaSe dual Schottky diode device both experimentally and theoretically [3]. As a striking difference to previous 2D material investigations, we introduce an alternative device architecture which does not rely on manual layer-bylayer stacking. Instead, the concept employs vertical monolayer CVD graphene [4] on GaSe as heterojunctions and a lateral GaSe channel allowing the utilization of multilayer 2D materials. Implementation of gate electrodes on top of the graphene contacts on GaSe enables the modulation of the Fermi energy of graphene (but not that of the GaSe channel) resulting in a controllable and switchable device. In transport measurements, a strong tunable current rectification was observed by the modulation of the Fermi level of graphene with the gate voltage. Transport measurements revealed strong current rectification and an on/off ratio as high as 103 underlining the importance of GaSe among other potential 2D materials. Detailed theoretical models were used to gain fundamental understanding of the operation mechanisms of the double diode device. Effective gate voltage determined by the drainsource voltage is one key factor for the device operation. Both experimental and theoretical results showed that the threshold

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voltage is shifted by the gate voltage enhancing the forward current modulation suggesting that dual Schottky junction device can also be exploited for various sensor applications. This device concept is expected to be useful for the progress of 2D material-based electronics making device processing compatible with conventional semiconductor technology.

References [1] [2] [3] [4]

L. Karvonen, A. Säynätjoki, S. Mehravar, R. D. Rodriquez, S. Müller, D.R.T. Zahn, S. Honkanen R.A. Norwood, N. Peyghambarian, K. Kieu, H. Lipsanen, J. Riikonen, Sci. Rep. 5 (2015) 10334.

A. Saynatjoki, L. Karvonen, J. Riikonen, W. Kim, S. Mehravar, R.A. Norwood, N. Peyghambarian, H. Lipsanen, K. Kieu ACS Nano 7 (2013) 8441.

W. Kim, C. Li, F.A. Chaves, D. Jiménez, R.D. Rodriguez, J. Susoma, M.A. Fenner, H. Lipsanen, and J. Riikonen, Adv. Mater. Available online, doi:10.1002/adma.201504514.

J. Riikonen, W. Kim, C. Li, O. Svensk, S. Arpiainen, M. Kainlauri, H. Lipsanen, Carbon 62 (2013) 43.

Figures

Figure 1: a) Illustration of the device structure b) measured and c) simulated I-V characteristics.

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Two-dimensional Materials as Optically Unique Identifiers J. Roberts, B. J. Robinson, Y. J. Noori, C. S. Woodhead, O. Kolosov, V. I. Falâ&#x20AC;&#x2122;ko, R. J. Young Lancaster University, Physics Department, Lancaster, UK j.roberts@lancaster.ac.uk

As technology has progressed, the trust of everyday interactions has inadvertently been undermined by the sophistication and availability of modern resources. To handle this issue, authentication strategies are implemented to provide proof of identities. Devices providing unique and reproducible fingerprints in response to an applied challenge can supply such identities.

To generate these distinct signatures, physically unclonable functions (PUFs) [1] are commonly utilised. The imperfect manufacturing process used to fabricate these devices provides structures that contain inherent randomness whilst containing a physical attribute that is simple to measure. Due to their physical nature, these structures do not rely on the privacy of stored secrets and can provide hard-to-predict unique identities for authentication in response to a challenge. However, the character of their classical design not only limits their size but also causes vulnerabilities in their security.

In our recent work [2], we show that the fluctuations in the current-voltage spectra of resonant tunnelling diodes (RTDs) containing quantum wells presents a straightforward yet robust measurement that can function as a PUF without conventional resource restrictions, in what we name a QC-PUF. As an alternative to the reported QC PUF, which relies on circuitry, we have devised a solution that uses an optical measurement, utilising the desired properties of two-dimensional materials. Here, we are interested in the sample-to-sample variations in the photoluminescence from a given 2D material, as demonstrated in Fig.1 (left panel). The practicality of such devices rely on scalability, therefore we have fabricated samples containing thin films of MoS2 and WS2 by the Langmuir-Blodgett technique [3], displayed in Fig. 1 (right panel), for the first time. As a result of the non-uniform thickness and coverage, these thin films show large-area photoluminescence where the wavelength, intensity and linewidth depends highly on position. Importantly, these devices are impossible to clone even with state-of-the-art technology, thus providing a novel authentication strategy based on two-dimensional nanomaterials.

References [1] [2] [3]

R. Pappu, B. Recht, J. Taylor & N. Gershenfeld, Science, 5589 (2002) 2026-2030.

J. Roberts, I. E. Bagci, M. A. M. Zawawi, J. Sexton, N. Hulbert, Y. J. Noori, M. P. Young, C. S. Woodhead, M. Missous, M. A. Migliorato, U. Roedig & R. J. Young, Scientific Reports, 5 (2015) 16456.

I. Langmuir, JACS, 39(9) (1917) 1848-1906.

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Figures

Wavelength 830.0

18 16

836.0

y-position (um)

14 12

842.0 10 8

848.0

6 4 2 2

4

6

8

10 12 14 16 18 20

x-position (um)

Figure 1: A typical photoluminescence map from a 2D flake (left) and the operation principle of Langmuir-Blodgett deposition (right).

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Growing vertical in the flatland Joshua A. Robinson The Pennsylvania State University, University Park, PA, 16802 USA jrobinson@psu.edu

The last decade has seen nearly exponential growth in the science and technology of twodimensional materials. Beyond graphene, there is a huge variety of layered materials that range in properties from insulating to superconducting. Furthermore, heterogeneous stacking of 2D materials also allows for additional “dimensionality” for band structure engineering. In this talk, I will discuss recent breakthrughs in two-dimensional atomic layer synthesis and properties, with afocus on the impact metal-organic chemical vapor deposition can have toward scalable production of such layers. Our recent works include development of an understanding of substrate impact on 2D layer growth and properties, doping of 2D materials with magentic elements, selective area synthesis of 2D materials, and the first demonstration of 2D gallium nitride (2D-GaN). Our work and the work of our collaborators has lead to a better understanding of how substrate not only impacts 2D crystal quality, but also doping efficiency in 2D materials, and stabalization of nitrides at their quantum limit.

References [1] [2] [3]

[4] [5] [6]

Z.Y. Al Balushi, K.Wang, R.Krishna Ghosh, R.A. Vilá, S.M. Eichfeld, P.A. DeSario, D.F. Paul, J.D. Caldwell, S.Datta, J.M. Redwing, J.A. Robinson; Graphene stabilization of twodimensional gallium nitride; arXiv preprint:1511.01871 Eichfeld, S. M.; Hossain, L.; Lin, Y.-C.; Piasecki, A. F.; Kupp, B.; Birdwell, A. G. G.; Burke, R. A.; Lu, N.; Peng, X.; Li, J.; et al. Highly Scalable, Atomically Thin WSe2 Grown via MetalOrganic Chemical Vapor Deposition. ACS Nano 2015.

Y.C. Lin, C.-Y. Chang, R. Ghosh,J.Li, H.Zhu, R.Addou, B.Diaconescu, T.Ohta, X.Peng, N.Lu, M.J. Kim, J.T. Robinson, R.M.Wallace, T.Mayer, S.Datta, L.J. Li, J.A. Robinson; Atomically Thin Heterostructures based on Single-Layer Tungsten Diselenide and Graphene; Nano Letters M. S. Bresnehan, G. Bhimanapati, K. Wang, D.Snyder, J.A.Robinson; Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers; ACS Appl.

Mater. Interfaces, 6, 16755–16762 (2014) S.M. Eichfeld, C.M. Eichfeld, Y.C. Lin, L. Hossain, J.A. Robinson; Rapid, non-destructive evaluation of ultrathin WSe2 using spectroscopic ellipsometry; APL Materials 2 (9), 092508 Y.C. Lin, N. Lu, N. Perea-Lopez, J. Li, C.H. Lee, Z.Lin, P.N. Browning, M.S. Bresnehan, L. Calderin, M.J. Kim, T.S. Mayer, M. Terrones, J.A. Robinson; Direct Synthesis of van der Waals Solids on Epitaxial Graphene; ACS Nano 8 (4), 3715-3723 (2014)

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Electronic properties of transition metal monochalcogenides A. S. Rodin, Lidia C. Gomes, A. Carvalho, A. H. Castro Neto Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore alerodin@gmail.com

Transition metal monochacogenides are a new addition to the ever-growing library of 2D materials. Combining the corrugated structure of black phosphorus with the dielemental nature of the majority of other two-dimensional structures, these materials possess a highly non-trivial band structure with multiple valleys located away from the high-symmetry points.

Because of this, studying these materials theoretically is a challenging task which is best accomplished by a combination of ab initio calculations and analytical methods. The purpose of this talk is to provide an overview of these fascinating compounds and highlight the properties which set them apart from other 2D materials. In addition, potential applications, which depend strongly on the material properties, will be introduced.

References [1]

A. S. Rodin, Lidia C. Gomes, A. Carvalho, A. H. Castro Neto, "Valleytronics in tin (II) sulfide", Phys. Rev. B (2016), Accepted.

Figures

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Graphene as enabling material for infrared plasmonic biosensors Daniel Rodrigo1, Odeta Limaj1, Davide Janner2, Dordaneh Etezadi1, F. Javier García-deAbajo2,3, Valerio Pruneri2,3, Hatice Altug1 1 Institute of BioEngineering, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland 2 ICFO - Institut de Ciències Fotòniques, The Barcelona Inst. of Science and Technology, Spain 3 ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain hatice.altug@epfl.ch

We present the first infrared biosensor using graphene and show the potential of the unique opto-electronic properties of graphene for plasmon-enhanced biosensing [1]. In particular, we demonstrate a graphene biosensor with dynamic spectral tunability and with an unprecedent sensitivity in detecting simultaneously the refractive-index and vibrational fingerprints of protein molecules.

A plasmonic resonance is excited in a graphene nanoribbon array (GNRA), appearing as an extinction peak in its infrared spectrum. By applying a biasing voltage, the plasmonic resonance is dynamically tuned across the vibrational bands of proteins. The sensor spectra is monitorized upon the formation of a protein bilayer (protein A/G and IgG antibody), showing dramatic changes that evidence its high sensitivity. The first effect observed is a very strong redshift of the plasmonic resonance, corresponding to the detection of the protein refractive index. The second effect is the formation of two spectral dips at 1660 and 1550cm-1, which correspond to the vibrational bands of proteins (amide I and II). These fingerprints are only detectable when the graphene plasmonic resonance overlaps amide bands enhancing the molecule vibrations. Thanks to the extreme field confinement in graphene, we detect redshifts and vibrational fingerprints, 6 and 3 times higher than in current state-of-the-art metalbased infrared biosensors.

In conclusion, graphene brings new spectrally-dynamic and highly-confined plasmonics to mid-IR, opening exciting and unforeseen possibilities for biosensing.

References [1]

D. Rodrigo, O. Limaj, D. Janner, D. Etezadi, F.J. Garcia-de-Abajo, V. Pruneri and H. Altug, "Mid-infrared Plasmonic Biosensing with Graphene," Science, vol. 349, Issue 6244, pp.165-168 (2015).

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Figures

Figure 1: Conceptual representation and SEM micrograph of the graphene plasmonic biosensor.

Measured extinction spectra before (dashed line) and after (solid line) protein immobilization

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Graphene integrated photonics for next generation optical communications Marco Romagnoli Consorzio Nazionale Interuniversitario per le Telecomunicazioni (CNIT), via Moruzzi 1, 56124 Pisa, Italy marco.romagnoli@cnit.itl

Datacom and Telecom are continuously evolving in terms of bandwidth, consumption and cost. The general request is bandwith increase with no change or even reduction of overall consumption and cost. According to the Ethernet roadmap the bandwidth doubles every two years [1]. The actual candidate technology for large volume and low cost is Si Photonics [2]. With Si Photonics it is possible to realize electro-refractive modulators and Ge based detectors exceeding 56Gb/s bandwidth in a single channel and at 28Gb/s this is already a product [3]. This technology has been widely studied and, for large volumes and for bandwidth of 28Gb/s or more is competitive with respect to III-V technologies or discrete photonic micro assemblies. However the Datacom roadmap requires cost /performance continuous improvements and technological limits may limit the scalability of the existing technologies.

Graphene offers electro-absortption [4] and electro-refraction [5] effect for modulators and thermoelectric effect for the detection [6]. Graphene layers can be transferred on waveguides in the postprocessing phase, the supporting waveguide has very limited requirements because no dopants are required for operating the devices. Silica, Si, or even polymer waveguides are all devisable because active functionalities will depend on the post-processed graphene layers. Graphene based photonics is proven by design on the base of material models verified by characterizations.[7] From theory grapheme photonics can be competitive with respect to Si Photonics but experimental verifications have to confirm this claim. Even though modulators and detectors have been proven, a new generation of designs is required to improve further performances. One issue is that graphene modulators are limited by the electron mobility of the transferred graphene. In order to increase mobility graphene has to be encapsulated with a barrier material that decouples graphene from the external materials. h-BN encapsulation can maintain mobility as large as 104 m 2 /(Vs). Lack of large mobility induces both insertion loss and dynamic range reduction in the modulator, increase of resistivity in the contacts and in the graphene fingers from the active region to the electrode. [8] Graphene electro-optical properties are also interestingly independent of the wavelength. In comparison Si Photonics is limited in the spectral range to 1600nm in which Ge detectors can absorb and to Si absorption edge at 1100nm on the other hand. In fact Si Potonics is mainly used for the O (1265 â&#x20AC;&#x201C; 1390nm) and C (1530 â&#x20AC;&#x201C; 1560nm) band of the telecom windows.

Graphene spectral range can be easily extended from visible through 2000nm and beyond.

This offers a great advantage in terms of power consumption because a course wavelength separation in a very wide range allows many channels operating in uncooled systems with no thermal control.

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Graphene fabrication on a large area is another important topic that would allow wafer scale manufacturing. Presently CVD graphene transfer from Cu substrate on the final wafer ensures best performance in terms of uniformity and electron mobility even though the method requires further developments to increase reproducibility and stability. Other alternative methods are considered but presently those are not mature yet.

In this presentation all aspects of graphene technology and photonics devices for Datacom applications will be reviewed with focus on feasibility and compliance with existing technologies.

References [1] [2] [3] [4] [5] [6]

[7] [8]

J. D’Ambrosia, S. G. Kipp, ‘The 2015 Ethernet Roadmap’, www.ethernetalliance.org Y. Arakawa et al. "Silicon Photonics for Next Generation System Integration Platform’, IEEE Communications Mag., p.72, March 2013.

Cisco CPAK for 100-Gbps Solutions, www.cisco.com Liu, M., X. Yin, X. Zhang, ‘Double-layer graphene optical modulator’, Nano Lett. 12, 1482 (2012).

M. Mohsin, D. Neumaier, D. Schall, M. Otto, C. Matheisen, A. L. Giesecke, A. A. Sagade, H. Kurz, ‘Experimental verification of electro-refractive phase modulation in graphene’, Scientific Reports 5, 10967 (2015); R. J. Shiue, Y Gao, Y. Wang, C. Peng, A. D. Robertson, D. K. Efetov, S. Assefa, F. H. L. Koppens, J. Hone, D. Englund, ’High-Responsivity Graphene–Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit’, Nano Lett, (September 2015) Y.-C. Chang, C.-H. Liu, C.-H. Liu, Z. Zhong, and T. B. Norris, “Extracting the complex opticalconductivity of mono- and bilayer Graphene by ellipsometry,” Appl. Phys. Lett.

104(26), 261909 (2014) V. Sorianello, M. Midrio, M. Romagnoli, ‘Design Optimization of Single and Double Layer grapheme Phase Modulators in SOI’, Opt. Expr. 23, 6478 (2015).

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Supramolecular approaches to 2-D materials: from complex structures to sophisticated functions Paolo Samorì ISIS, Université de Strasbourg & CNRS, 8 allée Gaspard Monge, 67000 Strasbourg, France samori@unistra.fr

Supramolecularly engineered hybrid materials containing graphene are key multifunctional systems for applications in (opto)electronics and energy. The tuning of their dynamic physical and chemical properties can be achieved via tailored covalent or non-covalent interactions with ad-hoc macromolecules.[1] My lecture will review our recent findings on: (i) The harnessing of the yield of exfoliation of graphene in liquid media by mastering the supramolecular approach via the combination with suitably designed functional molecules possessing high affinity for the graphene surface, leading ultimately to the bottom-up formation of optically responsive graphene based nanocomposites for electronics. [2] (ii) The tuning of the graphene properties by combining them with organic semiconductors as a strategy both to promote hole mobility in an otherwise electron transporting material and to exploit the tunable ionization energy of thermally annealed liquid phase exfoliated graphene to modulate the transport regime as well as to fabricate new memory devices.[3] (iii) The bottom-up formation of graphene based 3D covalent frameworks with tunable intersheet distance, exhibiting large specific surface areas which determine extremely high performance in supercapacitors.[4] (iv) The local thermal reduction of graphene oxide using a laser writer in order to develop very smooth, ultra thin, highly transparent and extremely conducting reduced graphene oxide patterns that can operate as highly sensitive ozone sensor.

Our approaches provide a glimpse on chemist’s toolbox to generate multifunctional graphene based nanocomposites with ad-hoc properties to address societal needs in electronics and energy applications.

References [1] [2]

(a) A. Ciesielski, P. Samorì, Chem. Soc. Rev. 2014, 43, 381–398. (b) A. Ciesielski, P. Samorì, Adv. Mater. 2016 in press (DOI: 10.1002/adma.201505371). (a) A. Ciesielski, S. Haar, M. El Gemayel, H. Yang, J. Clough, G. Melinte, M. Gobbi, E. Orgiu, M.V. Nardi, G. Ligorio, V. Palermo, N. Koch, O. Ersen, C. Casiraghi, P. Samorì, Angew. Chem. Int. Ed. 2014, 53, 10355–10361. (b) S. Haar, A. Ciesielski, J. Clough, H. Yang, R. Mazzaro, F. Richard, S. Conti, N. Merstorf, M. Cecchini, V. Morandi, C. Casiraghi, P. Samorì, Small 2015, 11, 1691-1702. (c) M. Döbbelin, S. Haar, M. Bruna, S.

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[3] [4]

Osella, F. Richard, A. Minoia, R. Mazzaro, E. Adi Prasetyanto, L. De Cola, V. Morandi, R. Lazzaroni, A.C. Ferrari, D. Beljonne, A. Ciesielski, P. Samorì, 2016 submitted. (a) M. El Gemayel, S. Haar, F. Liscio, A. Schlierf, G. Melinte, S. Milita, O. Ersen, A. Ciesielski, V. Palermo, P. Samorì, Adv. Mater. 2014, 26, 4814-4819. (b) T. Mosciatti, S. Haar, F. Liscio, A. Cieselski, E. Orgiu, P. Samorì, ACS Nano, 2015, 9, 2357–2367.

X. Zhang, A. Ciesielski, F. Richard, P. Chen, E. Adi Prasetyanto, L. De Cola, P. Samorì, Small 2016 in press (DOI: 10.1002/smll.201503677).

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Graphene film mass production and application in distributed flexible sensors Haofei Shi Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, China Chongqing Graphene Technology Co. Ltd., China shi@cigit.ac.cn

In this talk, Iâ&#x20AC;&#x2122;d like to present our recent progress on graphene film production by chemical vaper deposition. The discussion will be mainly focused on the cost, yield, and practical applications. I will also demonstrate how graphene film and graphene nanowall be used in distributed flexible sensors, to detect pressure, strain and temperature with considerable accuracy.

References [1] [2] [3] [4]

Xuefen Song et. al., 3-D conformal graphene for stretchable and bendable transparent conductive film, J. Mater. Chem. C, 2015, 3, 12379-12384.

Xuefen Song et. al., Direct versatile PECVD growth of graphene nanowalls on multiple substrates, Mat. Lett. 2014, 137, 25-28.

Jun Yang et. al. Wearable temperature sensor based on graphene nanowalls, RSC Adv., 2015,5, 25609-25615.

Dapeng Wei et. al. Laser direct growth of graphene on silicon substrate, Appl. Phys.

Lett. 2012, 100, 023110.

Figures

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Proximity induced ferromagnetism and spinorbit coupling in graphene Jing Shi, Z.Y. Wang, C. Tang, B.W. Yang, and Y. Barlas Department of Physics & Astronomy, University of California, Riverside, CA 92521, USA jing.shi@ucr.edu

A topological gap and the associated quantized anomalous Hall effect have been predicted for graphene in the presence of both exchange interaction and spin-orbit coupling. Although standalone graphene has no exchange interaction and negligibly week spin-orbit interaction, due to its open two-dimensional structure, graphene can acquire both interactions by proximity coupling to magnetic insulators or materials with strong spin-orbit interaction such as transition metal dichalcogenides. In this talk, I will present our experimental results on the proximity effects in two types of devices: graphene on yttrium iron garnet and WS2 on graphene. In the former, graphene is coupled to a magnetic insulator which induces ferromagnetism as revealed by the anomalous Hall effect. The anomalous Hall conductivity reaches ~ 20% of the predicted quantized anomalous Hall conductivity 2e2/h. The induced exchange strength is as large as room temperature, but it varies from device to device. In the latter devices, graphene is coupled to layered WS2 which imparts the spin-orbit interaction to graphene via hybridization. By directly comparing the magnetoresistance data in uncovered and WS2-covered graphene devices, it is clear that WS2-covered graphene acquires Rashba spin-orbit coupling. These results indicate that both exchange and spin-orbit interactions can be induced by proximity coupling with neighboring materials. Further tuning of the interaction strength may be possible..

References [1]

Z.Y. Wang, C. Tang, R. Sachs, Y. Balars, and Jing Shi, Phys. Rev. Lett. 114 (2015), 016603.

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Figures

Figure 1: Anomalous Hall resistivity as a function of the applied magnetic field for different gate voltages in both electron and hole regions.

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Multilevel resistive switching memory based on two-dimensional materials using simple solution process Gwang Hyuk Shin, Choon-Ki Kim, Gyeong Sook Bang, Byung Chul Jang, Myung Hun Woo, Yang-Kyu Choi, and Sung-Yool Choi School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 34141 Daejeon, Korea Sungyool.choi@kaist.ac.kr

Resistive switching memory has attracted great attention due to easy fabrication with simple structure as well as outstanding non-volatile memory performance including fast switching speed and low power consumption.[1-3] As a method of maximizing information storage density, the multi-level cell application (MLC) is one of the most promising solutions.

The MLC in resistive switching memory has been widely reported in various materials such as polymers and binary metal oxides.[4-6] However, an MLC operation based on only two dimensional materials has not been demonstrated yet. Here, we report the multilevel resistive switching memory based on graphene oxide (GO) and MoS2 using simple solution process. MoS2 nanosheets, which is exfoliated by Li intercalation process, were successfully embedded between two GO thin films using a spin-coating process. The GO/MoS2/GO stacks result in significant On/Off current ratio increases from ~102 for GO-only devices to > 104 for devices with MoS2 nanosheet. Excellent multilevel non-volatile memory performance including >104 s retention time, >102 endurance cycle without severe degradation, and at least four multiple resistance states were also demonstrated. Furthermore, we systematically investigated the resistive switching mechanism that trapped space charges in MoS 2 deep trap sites determine the number of resistance states which could be modulated by electrical bias. These results indicate that MoS2 nanosheets could be utilized as good charge storage materials enabling the MLC operation.

References [1] [2] [3] [4] [5] [6]

Hwang, C. S. et al., Adv. Electron. Mater., 1 (2015) 1400056.

Jeong, D. S. et al., Rep. Prog. Phys., 75 (2012) 076502.

Yang, J. J. et al., Nat. Nanotechnol., 3 (2008) 429-433.

Yoon, J.H. et al., Adv. Mater., 27 (2015) 3811-3816.

Choi, S.J. et al., Adv. Mater., 11 (2011) 3272-3277.

Hwang, S.K. et al, Nano Letter, 12 (2012) 2217-2221.

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Thermal and elastic properties of MoS2 nanosheets M. Sledzinska1, B. Graczykowski1, D. Saleta Reig1, M. Placidi2, A. El Sachat1, J.S. Reparaz1, F. Alzina1, B. Mortazavi3 , R. Quey4, and C. M. Sotomayor Torres1,5 1 Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Spain 2 Catalonia Institute for Energy Research (IREC), Spain 3 Advanced Materials Multiscale Modeling, Institute of Structural Mechanics, BauhausUniversität Weimar, Germany 4 Ecole des Mines de Saint-Etienne, CNRS, France 5 Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain marianna.sledzinska@icn.cat

Transition metal dichalcogenides, such as MoS2, are one of the 2D materials which have recently attracted a lot of attention because of their optical properties, such as the thickness-dependent band-gap transition and large optical absorption, which covers almost the whole visible spectrum [1]. At the same time they show excellent room-temperature carrier mobility with a high on-off ratio making them perfect candidates for nano-electronics.

However, despite these exciting properties, the future of 2D materials will depend on the progress in fabrication of nano-devices and ensuring their efficient operation.

In this work we address the issue of nanofabrication by developing a technique for transferring large areas of the CVD-grown, MoS2 nanosheets from the original substrate to another arbitrary substrate and onto holey substrates, in order to obtain free-standing structures. The method consists of a polymer- and residue-free, surface-tension-assisted wet transfer, in which we take advantage of the hydrophobic properties of the MoS2. The methods yields better quality transferred layers, with fewer cracks and defects, and less contamination than the widely used PMMA-mediated transfer and allows fabrication of fewnm thick, fee-standing structures with diameters up to 100 µm.

On the free-standing samples thermal measurements were performed using contactless Raman thermometry [2], which revealed a strong reduction in thermal conductivity down to 0.5 W/mK in the in-plane direction. The results were explained using finite elements method simulations for a polycrystalline film. We have also found an unusual elastic behavior of the thin films, measured with Brilluin spectroscopy, which manifests itself as a reduction of the acoustic phonon group velocity.

Understanding thermal and elastic properties of MoS2 can give an insight on the thermal transport in ultra-thin semiconducting films, especially taking into account amount of layers and grain sizes in polycrystalline materials. The possibility of tailoring thermal conductivity and Young modulus by controlling the grainsizes in the polycrystalline materials offers multiple applications for the future devices.

References [7] [8]

D Novoselov, K.S., et al., Proc Natl Acad Sci USA, 102 (2005) 10451.

Reparaz, J.S., et al. Rev Sci Instrum, 85 (2014) 034901.

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Ab-initio calculations and simple models of electronic excitations in 2D materials and heterostructures Kristian Sommer Thygesen Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, Fysikvej 1, Kgs. Lyngby, Denmark thygesen@fysik.dtu.dk

Many-body calculations based on the GW approximation to the electron self-energy and the Bethe-Salpeter equation (BSE) for the density response function are powerful methods for predicting band structures and optical excitations in real materials from first principles. We illustrate the high accuracy obtained by these methods through examples from our computational 2D materials database [1]. In 2D materials electron-electron interaction effects are particularly important because of the weak dielectric screening resulting in large self-energy corrections to band energies and strong excitonic effects. We show that the exciton binding energy can be approximated by a simple 2D Hydrogenic model taking an effective 2D dielectric constant and the exciton mass as input. Remarkably, the exciton binding energy depends only weakly on the exciton mass, and consequently the binding energy is found to scale directly with the size of the band gap – an effect unique to 2D excitons [2]. The simple Hydrogenic model also allows us to obtain the field-induced dissociation rates of 2D excitons by the technique of complex scaling to compute resonance life times. We show that the dissociation rates can be tuned significantly by embedding the active 2D material in a van der Waals heterostructures [3]. In general, periodic ab-initio calculations for van der Waals heterostructures are complicated by the incommensurable nature of the interfaces. We show that by neglecting the effect of hybridization and thus assuming a purely electrostatic coupling between the layers, it is possible to compute the dielectric properties of large incommensurable van der Waals heterostructures from the dielectric function of the individual layers [4]. The latter can be calculated once and for all and stored in a database. We illustrate how the Quantum Electrostatic Heterostructure (QEH) model can be used as a tool for modeling excitons, plasmons, and optical properties of van der Waals heterostructures [5].

References [1] [2] [3]

F. A. Rasmussen and K. S. Thygesen, “Computational 2D Materials Database: Electronic Structure of Transition-Metal Dichalcogenides and Oxides”, J. Phys. Chem.

C 119, 13169 (2015) Thomas Olsen, Simone Latini, Filip Rasmussen, and Kristian S. Thygesen, “Simple screened hydrogen model of excitons in two-dimensional materials”, Phys. Rev. Lett.

116, 056401 (2016) Sten Haastrup, Simone Latini, and K. S. Thygesen, “Field-induced dissociation of excitons in MoS2/hBN heterostructures”, arXiv

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[4] [5]

K. Andersen, S. Latini, and K. S. Thygesen, “Dielectric Genome of van der Waals Heterostructures”, Nano Letters 15, 4616 (2015) S. Latini, T. Olsen, and K. S. Thygesen, “Excitons in van der Waals heterostructures: The important role of dielectric screening”, Phys. Rev. B 92, 245123 (2015).

Figures

Figure 1: Left: The QEH model calculates the dielectric function of a vdWH from the dielectric functions of the individual 2D crystals assuming a pure Coulombic interaction between the layers.

Middle: Static dielectric function of 50 semiconducting TMDs. Right: Exciton binding energy in MoS 2 slabs of varying thickness. The exciton is calculated using a (quasi-)2D Hydrogen model with screened electron-hole interaction obtained from the QEH model. The results are seen to converge towards the bulk result showing the importance of dielectric screening relative to quantum confinement (not taken into account).

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Chiral plasmons without Magnetic Field Justin C W Song1, Mark S Rudner2 1 Institute of High Performance Computing, and Department of Physics, Nanyang Technological University, Singapore 2 Center for Quantum Devices and Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark justin.song.cw@gmail.com

Plasmons, the collective oscillations of interacting electrons, possess emergent properties that dramatically alter the optical response properties of metals. We predict the existence of a new class of plasmons â&#x20AC;&#x201C; chiral Berry plasmons (CBPs) â&#x20AC;&#x201C; for a wide range of two-dimensional metallic systems including, gapped Dirac materials. As we show, in these materials the interplay between Berry curvature and electron-electron interactions yields chiral plasmonic modes at zero magnetic field. The CBP modes are confined to system boundaries, even in the absence of topological edge states, with chirality manifested in split energy dispersions for oppositely directed plasmon waves. We unveil a rich CBP phenomenology and propose setups for realizing them, including in anomalous Hall metals and optically-pumped 2D Dirac materials. Realization of CBPs will offer a new paradigm for magnetic field-free, subwavelength optical non-reciprocity, in the mid IR-THz range, with tunable splittings as large as tens of THz, as well as sensitive all-optical diagnostics of topological bands.

References [1]

Justin CW Song, Mark S Rudner, arXiv: 1506.04743.

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Photophysics of 2D nanosystems: Raman and Ultrafast Pump-Probe Spectroscopy A.K. Sood Department of Physics, Indian Institute of Science, Bangalore 560 012, India asood@physics.iisc.ernet.in

My talk will focus on the rich photophysics of graphene, graphene nanoribbons, single and a few layer MoS2, single layer black phosphorous (Phosphorene) and MoT2/graphene hetrostructure, probed using electrical transport along with Raman and ultrafast spectroscopies in the visible as well as in the terahertz range. Insitu Raman spectroscopy of electrochemically top-gated field effect transistors made of grapheme [1] and phosphorene [2] will be presented to understand the phonon renormalization due to electron-phonon and electron-electron interactions in these systems. We show that phonons with Ag symmetry depend much more strongly and concentration of electrons than that of holes, whereas phonons with Bg symmetry are insensitive to doping.

Optoelectronic applications of two-dimensional systems require an in-depth understanding of the photoexcited carriers. The dynamics of the electrons, holes and excitons created by the pump laser in the visible range has been explored in our studies by probe lasers in the visible as well as in terahertz range. We show [3,4] that optical pump induced photoconductivity of graphene in the terahertz range can be either positive or negative depending on the Fermi energy and the carrier momentum relaxation time. The dominant processes contributing to the photo-conductivity are intraband scattering and secondary hot carrier generation due to Coulomb interaction of photo-excited carriers with the existing carriers in the Dirac cone. The cooling of photo-excited carriers is explained in terms of supercollision model. We will present our very recent results on a few layer MoS2 [5]. The dynamics is shown to be governed by the Auger processes as expected due to the unscreened Coulomb interactions in 2D systems.

The last part of my talk with present recent results[6] on enhanced photoresponsibility 20mA/W) using MoTe2-graphene vertical hetrostructures as compared to that of few layer MoTe2 (< 1mA/W).

References [1] [2]

[3]

Biswanath Chakraborty and A.K. Sood, Doping dependence of D-mode dispersion: Signatures of electron-electron interactions (2016) Biswanath Chakraborty, Satyendra Nath Gupta, Anjali Singh, Manabendra Kuiri, Chandan Kumar, D V S Muthu, Anindya Das, U V Waghmare and A.K. Sood, Electronhole asymmetry in the electron-phonon coupling in top-gated phosphorene transistor, 2D Materials 3, 015008 (2016).

Srabani Kar, D.R. Mohapatra, Eric Freysz and A.K. Sood, Tuning photoinduced terahertz conductivity in monolayer graphene: Optical pump terahertz probe spectroscopy, Phys. Rev. B 90, 165420 (2014).

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[4] [5] [6]

Srabani Kar, Jayanthi Swetha, Eric Freysz and A.K. Sood, Time-resolved spectroscopy of low frequency electronic resonances and optical pump induced terahertz photoconductivity in reduced graphene oxide membrane, Carbon 80, 762 (2014).

S. Kar, Yang Su, Rahul Nair, A.K.Sood, Probing photoexcited carriers in MoS2 laminate by time resolved optical pump terahertz probe spectroscopy. ACS Nano 9, 12004 (2015) Manabendra Kuiri, Biswanath Chakraborty, Arup Paul, Subhadip Das, A.K. Sood and Anindya Das, Enhancing photoresponsivity using MoTe2-graphene vertical heterostructures, Applied Physics Letters 108, 063506 (2016).

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Overview of 2D Nanomaterials Research in India A. K. Sood Department of Physics, Indian Institute of Science, Bangalore 560012, India asood@physics.iisc.ernet.in

I will present an overview of the work being done in India in the field of 2 D nanomaterials.

The work in Nanoscience picked up momentum in India after the Nanomission Project was launched a few years back by the Department of Science and Technology of Government of India.The funding support under the Nanomission project has contributed towards creating many groups in different institutions working on different themes .Even though there is no dedicated center in India so far on 2D materials , there are individual scientists and groups focusing on the physical ,chemical and biological aspects of graphene produced by different methods and other 2 D materials . I will attempt to summarize this work done in different Institutions in India.

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Growth of CVD-graphene on thermally annealed and electropolished Cu substrates Karthik Sridhara1, Boris Feigelson2, Jennifer K. Hite2, Michael S. Fuhrer4, D. Kurt Gaskill2, Luke O.Nyakiti1,3 1 Department of Material Science and Engineering, Texas A & M, College Station, TX 77840 USA 2 Electronic Science and Technology Division, Naval Research Laboratory, Washington DC 20375 USA 3 Department of Marine Engineering, Texas A & M Galveston, Galveston, TX 77554 USA 4 School of Physics, Monash University, Clayton VIC 3800, Australia karthik.sridhara@tamu.edu

The growth of graphene has been demonstrated using chemical vapor deposition (CVD) on high purity polycrystalline (99.99% purity) and single crystal Cu foils. Polycrystalline Cu foils are much more attractive than single crystal Cu due to extensive availability and lower costs.

However, Cu foils (~25 µm) used for graphene growth are ridden with surface defects such as native oxide of Cu (Cu(I)O, Cu(II)O), high root mean square (RMS) surface roughness (> 100 nm) and non-equiaxed grain structures (~ 1-10 µm) with elongated grain boundary due to its polycrystallinity. These defects arise mainly because the Cu foils are prepared using metallurgical cold rolling which imprints contaminants such as Al and induces non-equiaxed Cu grains. Due to the highly unsuitable nature of the Cu foils as obtained from vendors such as Alfa Aesar, it is challenging to obtain controllable, and reproducible large area graphene growth. To mitigate the unsuitable Cu surface, research groups have employed a variety of surface preparation techniques prior to graphene growth [1]: by removing the Cu native oxide using thermal annealing in H2 environment or dipping in Cu foils in nitric acid and using chemical mechanical polishing to reduce the surface roughness. These techniques offer adequate improvement of the Cu surface by removing native oxide and reducing the surface roughness. But these techniques still do not achieve nanometric level RMS roughness (~1-5 nm) desired for continuous large area graphene growth. Simultaneously, employing these techniques also introduce new type of surface defects on Cu in the form of etch pits due to the use of corrosive acids such as nitric acid for surface preparation of Cu prior growth.

In our previous work on hexagonal boron nitride (h-BN) [2], we used a two-step thermal annealing (in H2 environment at 1030°C) and electropolishing procedure to make Cu surface much more suitable for growth by removing the native oxide, and reducing the surface roughness. When we use this two-step procedure, we consistently observe a larger Cu grain size (> 100 µm) measured using optical and scanning electron microscope (SEM) micrographs, and surface roughness at the nanometric level (1.1-1.4 nm) as measured on a 100 µm2 scan area using atomic force microscopy (AFM). Growth of h-BN on these Cu foils lead to larger (~250%) and fewer (~60%) h-BN crystals as compared to growth on only thermally annealed Cu. We use the same surface preparation conditions to assess if this technique can be extended to graphene which is crystallographically similar to h-BN. We will report the details of our two-step surface preparation process and also the graphene growth

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metrics on these thermally annealed, electropolished Cu foils. SEM, AFM and Raman spectroscopy will be used to assess the size, count, thickness and quality of the graphene crystals grown.

References [1] [2]

C. Mattevi, H. Kim, and M. Chhowalla, A review of chemical vapour deposition of graphene on copper, J Mater Chem, vol. 21, no. 10, pp. 3324â&#x20AC;&#x201C;3334, 2010.

K. Sridhara. Growth of hexagonal boron nitride on electrochemically prepared polycrystalline Cu substrates. M.S. Thesis, University of Maryland, College Park, MD, 2014.

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V2O5/graphene hybrid as superior cathode for lithium-ion batteries Mateti Srikanth, Md Mokhlesur Rahman, Lu Hua Li, Qiran Cai, Ying Chen Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia m.rahman@deakin.edu.au; ian.chen@deakin.edu.au

To prevent the long-standing issues of low intrinsic electronic conductivity, slow lithium-ion diffusion and irreversible phase transitions on deep discharge of V2O5 electrode, a hybrid of V2O5 nanostructured with graphene is proposed as cathode for lithium-ion batteries. In this study, we develop a simple wet ball-milling method to create V2O5/graphene hybrid structure in which nanometre-sized V2O5 particles/aggregates are well embedded and uniformly dispersed into the crumpled and flexible graphene sheets generated by in-situ conversion of bulk graphite. The V2O5/graphene hybrid effectively leads to significant improvements in electronic conductivity, structural stability and ion diffusion, which in turn, results in excellent electrochemical performance. Low content of graphene results in a higher discharge capacity (185 mAh g-1) at 1C rate, while high content of graphene leads to a lower discharge capacity (157 mAh g-1), but much improved cycling stability. It is also demonstrated that this hybrid structure prevents self-aggregation of active materials and fully utilize the advantage of active materials by keeping effective contact area large between active materials, conductive additives and electrolyte. Therefore, this simple wet ball-milling method is offering new hope and possibilities to create various graphene based hybrid for large scale energy storage applications.

Keywords: graphene; in-situ generation; hybrid structure; cathode; lithium-ion batteries

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Graphene oxide linking layers: a versatile platform for biosensing Yu.V. Stebunov1, O.A. Aftenieva1, A.V. Arsenin1, and V.S. Volkov1,2 1 Moscow Institute of Physics and Technology, Institutsky 9, Dolgoprudny 141702, Russia 2 University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark stebunov@phystech.edu

Graphene oxide is opening up many new opportunities for biosensing applications. The honeycomb structure of carbon atoms makes possible its interaction with wide range of biological substances via stacking interaction with benzene rings. In addition, graphene oxide possesses different oxygen-containing functional groups, which allows the immobilization of biomolecules through strong covalent bonds. Covalent immobilization could be easily realized using existing biochemical immobilization protocols. Moreover, reduction of graphene oxide can finely tune chemical, electrical and optical properties of carbon material for specific biosensing applications. The main advantage of graphene oxide is the extremely high surface area of different structures made from this material, which provides high immobilization efficiency for wide range of biologically significant substances such as DNAs, RNAs, proteins, including antibodies and membrane proteins, viruses, and bacteria. Furthermore, graphene oxide can be easily produced in the form of waterdissolved flakes, which in turn can be used for scalable production of biosensors components.

Here, we describe a novel type of graphene oxide linking layers for highly sensitive biosensing based on surface plasmon resonance (SPR) [1]. During the last three decades, researchers have used only two technologies of linking layers for SPR biosensors, which are based on selfassembled monolayers of thiol molecules and on hydrogel layers. Using graphene oxide, we developed biosensor chips for existing commercial biosensors, whose sensitivity is higher than for commercial sensor chips available on the market [2] (Fig. 1). Graphene oxide sensor chips show three times higher sensitivity comparing to the sensitive commercial chips based on carboxymethylated dextran when using in the standard biosensing protocol based on streptavidin-biotin interaction. Moreover, the developed sensor chips are bioselective and can be used multiple times with a simple procedure of regeneration. The biosensing protocols based on streptavidin are widely used for the investigation of biochemical reactions with wide range of biological substances without the necessity to attach radiological or fluorescent labels to investigated objects. At present moment, SPR-based label-free biosensing has application in pharmaceutical industry, and it is included in the guidelines of the US Food and Drug Administration and of the European Medicines Agency for the testing of biotechnology-derived pharmaceuticals. Biopharmaceuticals have high molecular masses and reactions with them can be easily investigated by SPR providing many advantages over other methods. However, most of developing drugs are based on lowmolecular-weight substances, such as those acting on G-protein coupled receptors (GPCRs), which serve as targets for 40 percent of drugs on the market. At present moment, the investigation of drugs acting on GPCRs by SPR is not conducted due to insufficient sensitivity of SPR biosensors. Therefore, the implementation of graphene oxide linking layers in SPR

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biosensor chips could broaden the area of pharmaceutical applications of biosensors to all developing drugs and change the whole process of drug discovery and development.

References [1] [2]

F Y.V. Stebunov, O.A. Aftenieva, A.V. Arsenin, V.S. Volkov, ACS Appl. Mat. Interfaces 7 (2015), 21727-21734.

A.V. Arsenin, Yu.V. Stebunov. RU Patent Application No. 2527699 (Feb 2013); US Patent Application No. 20150301039 (Oct 2015).

Figures

Figure 1: Biosensor chips based on monolayer graphene, graphene oxide, and carboxyl graphene linking layers designed for use with a commercial SPR instrument.

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Optical Properties of Laterally-Confined Monolayer Semiconductors Nathaniel P. Stern1, Guohua Wei1, David A. Czaplewski2, Erik J. Lenferink1, Il Woong Jung2, and Teodor K. Stanev1 1 Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL, 60201, USA 2 Center for Nanoscale Materials, Argonne National Laboratory, 9700 S Cass Avenue, Argonne, IL 60439, USA n-stern@northwestern.edu

Size-dependent control of material properties in semiconductors is an important feature exploited for numerous fundamental and technological applications. In semiconductor quantum dots (QDs), the full three-dimensional confinement of carrier wavefunctions affords a high degree of optical and electronic tunability. In 2D semiconductors such as transition metal dichalcogenides (TMDs), out-of-plane vertical confinement arises naturally from the layered structure, but because of the small exciton Bohr radius of ~1 nm [1], size-dependent control using lateral confinement is challenging. Despite the observation of lateral confinement effects in monolayer nanoflakes [2] and non-classical light emission from localized TMD defects [3], systematic size-dependent control of optical and electronic properties of TMD monolayers is not well established. Here, we present measurements of the optical properties of laterally-confined monolayer semiconductor quantum dots created through controlled nanopatterning of single TMD layers into nearly circular nanoflakes. Sizedependent exciton energies are observed from lateral confinement in monolayers of MoS2 and WSe2. Our measurements show that the weak confinement regime of monolayer TMD QDs shares the valley polarization properties familiar from unprocessed monolayer TMDs [4,5].

This work is supported by the Institute for Sustainability and Energy at Northwestern, the U.S. Department of Energy (DE-SC0012130), the National Science Foundationâ&#x20AC;&#x2122;s MRSEC program (DMR-1121262), and Argonne National Laboratory. Use of the Center for Nanoscale Materials was supported by the U. S. Department of Energy under Contract No. DE-AC02-06CH11357.

N.P.S. is an Alfred P. Sloan Research Fellow.

References [1] [2] [3] [4] [5]

T. Cheiwchanchamnangij and W. R. Lambrecht, Phys. Rev. B 85 (2012) 205302.

Z. Gan, L. Liu, H. Wu, Y. Hao, Y. Shan, X. Wu, and P. K. Chu, Appl. Phys. Lett. 106, 233113.

A. Srivastava, M. Sidler, A. V. Allain, D. S. Lembke, A. Kis, and A. ImamoÄ&#x;lu, Nature Nanotech. 10 (2015) 491.

G.-B. Liu, H. Pang, Y. Yao, and W. Yao, New J. Phys. 16 (2014) 105011.

G. Wei, D. A. Czaplewski, E. J. Lenferink, T. K. Stanev, I.-W. Jung, and N. P. Stern, arXiv:1510.09135 (2015), http://arxiv.org/abs/1510.09135

Figures

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Figure 1: (a) AFM scan of a 1 Îźm x 1 Îźm region of patterned QDs with dot pitch of 150 nm. (b) Photoluminescence spectra from a flake of WSe2 from the QD (on dots) and unpatterned region (off dots). The QD blue shift of energy is evident.

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Gate Tunable Nonlinear Rashba spin splitting in transition metal dichalcogenide monolayers Jia-Tao Sun Institute of Physics, Chinese Academy of Sciences, Beijing, China jtsun@iphy.ac.cn

Single-layer transition-metal dichalcogenides (TMD) such as MoS2 and MoSe2 have unique electronic band structures, ideal for hosting many exotic spin-orbit phenomena such as Rashba effect. It has been widely accepted that Rashba-type spin splitting (RSS) is linearly proportional to the external gate electric field in metallic heterostructure interface or to potential gradient in polar materials. Here an extraordinary nonlinear dependence of RSS is surprisingly found in semiconducting TMDs monolayers under gate field using first-principles calculations. In contrast to a small, constant RSS in polar materials, the electrostatic potential gradient in non-polar TMDs gradually increases with gate voltage, resulting nonlinear RSS with a Rashba coefficient an-order-of-magnitude larger than that for materials of similar elemental mass. Based on a kâ&#x20AC;˘p model via symmetry analysis, we identify that the third-order anisotropic contribution is responsible for the extra-large nonlinear Rashba splitting. The gate tunable spin splitting found in semiconducting pristine TMD monolayers promises for future spintronics applications in that spin polarized electrons can be generated by external gating in an experimentally accessible way.

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Current flow paths in deformed graphene: from quantum transport to classical trajectories in curved space Nikodem Szpak1, Thomas Stegmann2 1 Fakult채t f체r Physik, Universit채t Duisburg-Essen, Duisburg, Germany 2 Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Mexico nikodem.szpak@uni-due.de

We compare two fundamentally different approaches to the electronic transport in deformed graphene: a) current flow paths obtained with the non-equillibrium Green's function (NEGF) method from the tight-binding model with local strain, b) classical trajectories for relativistic point particles moving in a curved surface with pseudo-magnetic field. The connection between them is established in the long-wave limit via an effective Dirac Hamiltonian in curved space. Geometrical optics approximation applied to focused current beams allows to directly compare the wave and the particle pictures. We obtain very good numerical agreement between the quantum and the semiclassical approaches for a fairly wide set of parameters, improving with the increasing size of the systems.

Combination of the curvature and the pseudo-magnetic field paves the way to new interesting transport phenomena such as bending or focusing (lensing) of currents depending on the shape of the deformation. It can find applications in designing ultrasensitive sensors or in nanoelectronics.

References [1]

T. Stegmann and N. Szpak, http://arxiv.org/abs/1512.06750.

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Figures

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High surface area graphene-related materials for hydrogen storage Alexandr Talyzin, Guillaume Mercier, Alexey Klechikov Department of Physics, Umea University, SE-901 87 Umea, Sweden alexandr.talyzin@umu.se

Ultra-high surface area graphene scaffold materials were prepared using thermal exfoliation of graphite oxides to produce reduced graphene oxide (rGO) which was modified using KOH activation and high temperature high pressure hydrogen annealing. Using optimized procedure we prepared highly porous graphene scaffold materials with specific surface area (SSA) values up to 3400 m 2 /g and pore volume up to 2.2 cm3 /g. The pore volume of activated graphene scaffold samples is superior compared to other nanoporous materials.

For example, comparable pore volume of ~2 cm3 /g is achieved in Metal Organic Framework (MOF) materials with about twice higher SSA values (~5000- 7000 m2 /g).

Graphene scaffolds are chemically inert and stable even after weeks of on air storage which is significant advantage compared to most of MOF materials.

The “graphene scaffold” structure created using the KOH activation procedure shows essentially microporous nature in contrast to pristine r-GO obtained by thermal exfoliation as revealed by both SEM imaging (Figure 1) and analysis of nitrogen sorption isotherms. Two peaks are typically observed in the pore size distribution plots simulated using slit pore QSDFT: first peak approximately at 0.7-0.8 nm and second at ~1.5 nm. The KOH activation of rGO helps to create 3D packing consisting of disordered, interconnected and highly defective graphene sheets, while hydrogen annealing broadens smallest pores and removes most of the residual oxygen (C/O=35 is achieved) [1].

Hydrogen uptakes were evaluated for rGO and of activated graphene samples with broad range of SSA values 300-3300 m2 /g which allowed to establish SSA vs H2 uptake trends for ambient and liquid nitrogen temperatures (Figure 2) [1-2]. Temperature dependence of hydrogen sorption was evaluated in a broad temperature interval (77-296 K). The maximal excess H2 uptake of 7.5 wt% at 77 K was achieved for samples with SSA over 3000 m2 /g which is among highest ever reported for carbon materials. A hydrogen storage value as high as 4 wt% was observed already at 193 K (120 bar H2), temperature of solid CO2, which can be easily maintained using common industrial refrigeration methods. The SSA values achieved in our experiments are still below 4000-5000 m2 /g theoretically predicted for highly porous perforated ordered graphene multilayers [3] which provides a promise for even further improved hydrogen storage of graphene scaffolds.

The hydrogen sorption trends revealed in our experiments for graphene-related materials demonstrate that H2 uptakes of “graphene” samples follow standard for all carbon materials trends and can predicted using BET SSA values extracted by analysis of nitrogen sorption isotherms [2]. Thus, the exceptional hydrogen storage properties of “graphene” (reduced graphene oxides) reported in some earlier studies are not confirmed. The same trends are found also for samples of so called “Graphene Oxide Framework” materials prepared using reaction of graphite oxides with benzene-1,4-diboronic acid (DBA) following procedure

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described in Ref [4]. Optimization of synthesis procedures allowed us to increase SSA of this material up to ~1000 m2 /g. The structure of GO/DBA samples cannot be considered to be framework with graphene sheets interconnected by DBA molecules as it is not compatible with revealed swelling of GO/DBA samples in polar solvents. Alternative models with graphene oxide structure pillared (but not linked) by DBA-derived molecular units are proposed [5].

Using swelling in polar solvents and expanded graphite/graphene oxide structures obtained by solution based insertion of various organic molecules for preparation of porous materials will be discussed.

References [1] [2] [3] [4] [5]

A. G. Klechikov, G. Mercier, P. Merino, S. Blanco, C. Merino and A. V. Talyzin, Microporous Mesoporous Mater., 210, (2015), 46–51.

A. Klechikov, G. Mercier, T. Sharifi, I. A. Baburin, G. Seifert and A. V. Talyzin, Hydrogen storage in high surface area graphene scaffolds, Chem.Comm., 51 , (2015), 1528015283.

I. A. Baburin, A. Klechikov, G. Mercier, A. V. Talyzin and G. Seifert, International Journal of Hydrogen Energy, 40, (2015), 6594–6599.

J. W. Burress, S. Gadipelli; J.Ford; J.M.Simmons, W.Zhou, T. Yildirim, Angew. Chem., Int. Ed. 49, (2010), 8902−8904.

G.Mercier, A.Klechikov, M. Hedenstrom, D. Johnels, I. A. Baburin, G.Seifert, R. Mysyk, and A.V. Talyzin, J.Phys.Chem C, (2015) published as early view.

Figures

Figure 1: SEM images recorded from a-r-GO sample with BET surface area of ~3300 m2 /g. The images show hierarchical size pore network (a, b) and also some layered structure on broken grain edge (c,d).

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Figure 2: H2 uptake (wt%) vs SSA trends evaluated using volumetric method and immersion cell for ar-GO samples at 296 K (120 bar) and 77 K (saturation value) before (■) and after H 2 annealing (■).

The trend is extended showing samples of r-GO (●) 13 and reference points for Mesoporous Carbon and Activated Carbon (●).

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Hierarchical Porous Graphene: CVD Growth on Metal Oxides for High-Rate Lithium-Sulfur battery and Superior Oxygen Evolution Electrocatalysis Cheng Tang, Qiang Zhang,* Hao-Fan Wang, Lin Zhu, Fei Wei* Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China zhang-qiang@mails.tsinghua.edu.cn (Q. Zhang) wf-dce@mail.tsinghua.edu.cn (F. Wei)

Structural hierarchy plays an important role in the biological world and functional materials with optimized properties and high efficiency. With a growing concern and urgent development of sustainable energy systems and next-generation energy storage technologies, hierarchical porous graphene (HPG) materials have been intensively investigated over the past decades, which are demonstrated as promising electrode materials for various systems, such as lithium-sulfur (Li-S) batteries, supercapacitors, metal-air batteries, and fuel cells, with a remarkable capacity, high efficiency, long stability, and excellent rate capability. The promising applications of the hierarchical sp2 carbon-based nanomaterials are highly dependent not only on their superior intrinsic physical properties, but also on their tunable structural characters. Despite of great progress, however, favorable regulation of their hierarchical porosity and multi-functionalities remains a challenge to extend their excellent properties from nanoscale to macroscale and thereby the practical applications.

Chemical Vapor Deposition (CVD) growth on the metal foil has been regarded as the most effective method to fabricate high-quality graphene films, while ineffective to modulate the structural hierarchy and criticized of its ultra-low production. Herein, we have creatively proposed a novel family of porous metal oxide templates for the catalytic CVD deposition of HPG materials, and scrupulously designed the process to modulate their properties towards satisfactory performances.

Firstly, a metal-embedded supported bifunctional catalyst was proposed for the in-situ growth of aligned carbon nanotube/graphene (ACNT/G) sandwiches via a two-step CVD growth, with the metal nanoparticles as catalysts for CNT formation and metal-oxide lamellar as hard template catalyst for graphene deposition.[1] NH3 was introduced during CVD to modify the chemical features (N-ACNT/G). Aligned CNTs and graphene layers were in situ anchored to each other, constructing a sandwich-like hierarchical architecture with efficient 3D electron transfer pathways and ion diffusion channels. The moderate chemical modulation induced by nitrogen doping introduced more defects and active sites to the carbon framework, thereby improving the interfacial adsorption and electrochemical behaviors. When the novel N-ACNT/G hybrids were used as cathode materials for Li-S batteries, greatly enhanced cyclic and rate performances were demonstrated. A high initial reversible capacity of 1152 mAh g-1 can be available at 1.0 C, maintaining ca. 880 mAh g-1 after 80 cycles, which was about 65 % higher than that of ACNTs. Even at a high current density of 5.0 C, a reversible capacity of ca. 770 mAh g-1 can be achieved. [2]

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Furthermore, porous CaO with low cost, facile purification, and promising cyclic utilization was firstly adopted as oxide catalysts for the CVD growth of graphene.[3] On one hand, the CaO can serve as effective catalysts to stimulate the CVD growth of ultra-thin graphene with a self-limiting behavior due to vast surface defects and step-edges. On the other hand, the precise replication of their structural hierarchy result in an integrated HPG framework with abundant micro-sized in-plane vacancies, meso-sized wrinkled pores, and macro-sized strutted cavities (CaO-G). The gas composition during CVD and nanostructure of catalysts significantly impact on the graphitization degree and hierarchical porosity of resultant materials. When applied in Li-S batteries, a high initial capacity of 434 mAh gcathode-1 can be achieved at 0.5 C, with an ultra-low cyclic fading rate of 0.11 % and high coulombic efficiency of 90 % without LiNO3 addition for initial 150 cycles. A 74 % retention of the capacity at 0.1 C can be manifested at a very high current rate of 5.0 C. Importantly, the HPG should not only be directly utilized as a hierarchical scaffold, but also can serve as effective regulators in composite fabrications, contributed from its tunable porosity, ultra-thin structure, hydrophobic surface and variable defects. A nitrogen-doped mesoporous graphene framework grown on mesoporous MgO templates was scrupulously designed to hybridize nanosized NiFe layered double hydroxides with an in-situ defectanchored nucleation and spatially confined growth, leading to a uniformly decorated nanosized active particles and strong coupled interface between active phase and conductive substrate.[4] The nNiFe LDH/NGF composite was demonstrated to overperform commercial Ir/C catalysts and compete favorably against reported alternatives for high-performance oxygen evolution reaction (OER) catalysis, with a remarkably low Tafel slope (~45 mV dec-1), a substantially decreased overpotential (~337 mV required for 10 mA cm-2), and enhanced durability.

These processes shed novel lights on the CVD fabrication of advanced graphene materials with porous metal oxide templates. It is instructive and expected to open up fresh perspectives and inspiring avenues on hierarchical graphene towards superior energy storage and oxygen electrocatalysis.

References [1] [2] [3] [4]

C Tang, Q Zhang, M-Q Zhao, G-L Tian, F Wei. Nano Energy, 7 (2014): 161-169.

C Tang, Q Zhang, M-Q Zhao, J-Q Huang, X-B Cheng, G-L Tian, H-J Peng, F Wei. Advanced Materials, 35 (2014): 6100-6105.

C Tang, B-Q Li, Q Zhang, L Zhu, H-F Wang, J-L Shi, F Wei. Advanced Functional Materials, 2015, DOI: 10.1002/adfm.201503726.

C Tang, H-S Wang, H-F Wang, Q Zhang, G-L Tian, J-Q Nie, F Wei. Advanced Materials, 30 (2015): 4516-4522.

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Figures

Figure 1: SEM image of a) N-ACNT/G and b) CaO-G, and c) TEM image of nNiFe LDH/NGF material. d) Li-S battery performances of N-ACNT/G and e) OER performances of nNiFe LDH/NGF

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Field-effect transistors for rapid on-site disease diagnostics A. Tarasov1,2, M.-Y. Tsai1, D. W. Gray3, N. Shields3, N. Creedon4, A. Montrose4, P. Lovera4, E. M. Flynn1, C. A. Joiner1, R. C. Taylor1, P. M. Campbell1, A. O'Riordan4, M. H. Mooney3, and E. M. Vogel1 1 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA 2 BioMed X Innovation Center, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany 3 Institute for Global Food Security, School of Biological Sciences, Queenâ&#x20AC;&#x2122;s University Belfast, Belfast,Northern Ireland, BT9 5AG, United Kingdom 4 Nanotechnology Group, Tyndall National Institute, University College Cork, Cork, T12R5CP, Ireland tarasov@bio.mx, alexey.tarasov@mse.gatech.edu

Field-effect transistors (FETs) based on large-area graphene [1, 2] and other two-dimensional (2D) materials such as MoS2 [3, 4] and WSe2 [5] can potentially be used as highly sensitive, low-cost and flexible biosensors in future point-of-care (POC) diagnostic devices. However, there have been few attempts to use these devices for quantifying molecular interactions and to compare their performance to established sensor technology. Here, gold-coated graphene FETs are used to measure the binding affinity of a specific proteinâ&#x20AC;&#x201C;antibody interaction. [6] Having a gold surface gives access to well-known thiol chemistry for the selfassembly of linker molecules. The results are compared with potentiometric silicon-based extended-gate sensors and a surface plasmon resonance system. The estimated dissociation constants are in excellent agreement for all sensor types as long as the active surfaces are the same (gold).

Furthermore, using the model pathogen Bovine Herpes Virus-1 (BHV-1) this study employs an extended-gate field-effect transistor (FET) for direct potentiometric serological diagnosis.[7] BHV-1 is a major viral pathogen of Bovine Respiratory Disease (BRD), the leading cause of economic loss ($2 billion annually in the US only) to the cattle and dairy industry. To demonstrate the sensor capabilities as a diagnostic tool, BHV-1 viral protein gE was expressed and immobilized on the sensor surface to serve as a capture antigen for a BHV-1-specific antibody (anti-gE), produced in cattle in response to viral infection. The gE-coated immunosensor was shown to be highly sensitive and selective to anti-gE present in commercially available anti-BHV-1 antiserum and in real serum samples from cattle with results being in excellent agreement with Surface Plasmon Resonance (SPR) and ELISA. The FET sensor is significantly faster than ELISA (<10 min), a crucial factor for successful disease intervention. This sensor technology is versatile, amenable to multiplexing, easily integrated to POC devices, and has the potential to impact a wide range of human and animal diseases.

Finally, tunneling field-effect transistors based on vertical stacks (heterostructures) of 2D materials will be discussed.[8] These band-to-band tunneling devices have a fundamentally different working principle, and can overcome the thermionic turn-on limit (or subthreshold swing) of conventional fieldeffect transistors,[9] which can potentially enable fast und ultrasensitive biosensors.

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References [1] [2] [3] [4] [5] [6] [7] [8] [9]

W. Fu, C. Nef, O. Knopfmacher, A. Tarasov, M. Weiss, M. Calame and C. Schonenberger Nano Lett. 11 (2011) 3597-600 W. Fu, C. Nef, A. Tarasov, M. Wipf, R. L. Stoop, O. Knopfmacher, M. Weiss, M. Calame and C. Schoenenberger Nanoscale 5 (2013) 12104-10 A. Tarasov, P. M. Campbell, M.-Y. Tsai, Z. R. Hesabi, J. Feirer, S. Graham, W. J. Ready and E. M. Vogel Adv. Funct. Mater. 24 (2014) 6389-400 A. Tarasov, S. Zhang, M.-Y. Tsai, P. M. Campbell, S. Graham, S. Barlow, S. R. Marder and E. M. Vogel Adv. Mater. 27 (2015) 1175-81 P. M. Campbell, A. Tarasov, C. A. Joiner, M.-Y. Tsai, G. Pavlidis, S. Graham, W. J. Ready and E. M. Vogel Nanoscale 8 (2016) 2268-76 A. Tarasov, M.-Y. Tsai, E. M. Flynn, C. A. Joiner, R. C. Taylor and E. M. Vogel 2D Mater. 2 (2015) 044008 A. Tarasov, D. W. Gray, M.-Y. Tsai, N. Shields, N. Creedon, A. Montrose, P. Lovera, A. O'Riordan, M. H. Mooney and E. M. Vogel Biosens. Bioelectron. 79 (2016) 669â&#x20AC;&#x201C;78 P. M. Campbell, A. Tarasov, C. A. Joiner, W. J. Ready and E. M. Vogel ACS Nano 9 (2015) 5000â&#x20AC;&#x201C;8 D. Sarkar, X. Xie, W. Liu, W. Cao, J. Kang, Y. Gong, S. Kraemer, P. M. Ajayan and K. Banerjee Nature 526 (2015) 91-5

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Spin relaxation anisotropy in graphene Bart Raes1, Jeroen E. Scheerder2, Marius V. Costache1, Frederic Bonell1, Juan F. Sierra1, Jo Cuppens1, Joris Van de Vondel2 and Sergio O. Valenzuela1,3 1 Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology,Campus UAB, Bellaterra, 08193 Barcelona, Spain 2 INPAC - Institute for Nanoscale Physics and Chemistry,Department of Physics and Astronomy, KU Leuven,Celestijnenlaan 200D, B-3001 Leuven, Belgium 3 Instituciรณ Catalana de Recerca i Estudis Avanรงats (ICREA), 08070 Barcelona, Spain SOV@icrea.cat

In recent years, graphene-based spintronics have shown impressive progress [1,2,3]. Spin relaxation lengths in graphene have been observed to be larger than several tens of micrometers and are already within the required range for technological applications [3,4].

This has been accomplished by a steady improvement of the quality of graphene and of the interfaces with contacting materials [1,3]. However, the microscopic mechanisms that determine the spin lifetime, and spin relaxation length, are still under heated debate [1,2].

This lack of understanding hampers graphene spintronics in reaching its full potential, as for applications it is desirable to achieve full control of the spin dynamics. The spin relaxation anisotropy, which can be quantified by the ratio between the spin lifetimes for perpendicular and parallel spin components to the graphene plane, is a key property that can provide information on the microscopic mechanisms that is not accessible by other means [1]. This is so because the anisotropy is determined by the preferential direction of the spin-orbit fields that may cause the spin relaxation. Despite such inherent interest, measurements of the spin lifetime anisotropy are scarce and limited to large carrier densities [5]. Here, we demonstrate a conceptually new approach that overcomes this limitation. The concept relies on spin precession measurements under oblique magnetic fields that generate an out-of-plane spin population, which is further used to evaluate the out-of-plane spin lifetime [6]. Our experiments demonstrate that the spin relaxation anisotropy of graphene on silicon oxide is independent of carrier density and temperature, and much lower than previously reported; indeed, within the experimental uncertainty, the spin relaxation is isotropic. Together with the gate dependence of the spin lifetime, this indicates that the spin relaxation is driven either by magnetic impurities or by randomly oriented spin-orbit fields, relative to the spin. These findings open the way for systematic anisotropy studies with tailored impurities and on different substrates, which are crucial to find a route to manipulate the spin lifetime in graphene and as such has important implications for both fundamental science and technological applications.

References [1] [2] [3] [4] [5] [6]

W. Han, R. K. Kawakami, M. Gmitra, and J. Fabian, Nat. Nanotechnol., 9 (2014) 324 S. Roche and S. O. Valenzuela, J. Phys. D, 47 (2014) 094011.

S. Roche et al, Graphene spintronics: the European Flagship perspective, 2D Materials 2 (2015) 030202.

M. Drรถgeler et al. arXiv: 1602.02725.

M. H. D. Guimarรฃes, et al. Phys. Rev. Lett., 113 (2014) 086602.

B. Raes, et al. (to be published)

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Room temperature long distance spin transport in chemical vapor deposited graphene M. Venkata Kamalakar1,2, Christiaan Groenveld1, André Danket1, and Saroj P. Dash1 1 Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden 2 Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden venkata.mutta@physics.uu.se

Graphene is an ideal spin transport medium for efficient spintronic devices. Since the first report of spin transport and precession in graphene [1], the graphene spintronics’ community has been able to achieve impressive progress in enhancing the spin lifetime and diffusion length in exfoliated graphene [2]. Such exfoliated flakes are limited in size and hence are unsuitable for large scale practical applications. Spin transport studies in wafer scale chemical vapor deposited (CVD) graphene have revealed relatively lower spin parameters (with spin lifetime ~ 100-200 ps) [3,4]. In this work, we report a very high spintronic performance of large area chemical vapor deposited (CVD) graphene on SiO2 substrate at room temperature [5]. Through non-local pure spin transport and precession measurements, we demonstrate spin communication over channel lengths extending up to 16 μm with a spin lifetime of 1.2 ns and a spin diffusion length ~ 6 μm at room temperature (Fig. 1). These spin parameters are not only up to six times higher than previous reports on CVD graphene, but are also the highest at room temperature for any form of pristine graphene on standard SiO2/Si substrates. Our detailed investigations involving various graphene channel lengths, carrier densities and temperatures demonstrate the observed performance over a wafer scale. These results elucidate that CVD graphene is an excellent material for long distance spin communication in possible future graphene channel based memory and logic applications.

References [1] [2] [3] [4] [5]

Tombros, N., Jozsa, C., Popinciuc, M., Jonkman, H. T. & van Wees, B. J. Electronic spin transport and spin precession in single graphene layers at room temperature. Nature 448, 571–574 (2007).

Ingla-Aynés, J., Guimarães, M. H. D., Meijerink, R. J., Zomer, P. J. & van Wees, B. J. 24 − μ m spin relaxation length in boron nitride encapsulated bilayer graphene. Phys. Rev. B 92, 201410 (2015).

Avsar, A. et al. Towards wafer scale fabrication of graphene based spin valve devices. Nano Lett. 11, 2363–8 (2011).

Fu, W., Makk, P., Bräuninger, M., Maurand, R. & Schönenberger, C. Large-scale fabrication of BN tunnel barriers for graphene spintronics. J. Appl. Phys. 116, 074306 (2014).

Kamalakar, M. V., Groenveld, C., Dankert, A. & Dash, S. P. Long Distance Spin Communication in Chemical Vapour deposited Graphene. Nat. Commun. 6, 6766 (2015).

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In-situ electrical measurements of Graphene Nanoribbons fabricated through Scanning Transmission Electron Microscopy L.Vicarelli 1, S.J.Heerema1, C. Dekker1, H.W. Zandbergen1 1 Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands l.vicarelli@tudelft.nl

We recently demonstrated a controllable and reproducible method to obtain suspended monolayer graphene nanoribbons with atomically defined edge shape [1]. Our method exploits the electron-beam of a Scanning Transmission Electron Microscope (accelerated at 300 kV) to create vacancies in the lattice by knock-on damage and pattern graphene in any designed shape. The small beam spot size (0.1 nm) enables close-to-atomic cutting precision, while heating graphene at 600o C during the patterning process avoids formation of beam-induced Carbon deposition and allows self-repair of the graphene lattice. Selfrepair mechanism is essential to obtain well-defined (zig-zag or armchair) edge shape and, if the electron beam dose is lowered, to perform non-destructive imaging of the graphene nanoribbons.

Drawing the electron-beam path with a software script, we were able to obtain reproducible graphene nanoribbons with sub 10 nm width. Using an in-house built microscopy holder equipped with electrical feedthroughs, we performed 2 and 4 wire measurements on several graphene nanoribbons, with different number of layers. Results show that our nanoribbons exhibit ohmic behaviour, with conductivity linearly proportional to the width. We also measured the conductivity as a function of temperature in the range 300-900 K, and found that it follows a semiconductor-like dependence, rather than metallic.

The fabricated nanoribbons were stable for several weeks after TEM sculpting. Ex-situ measurements were carried in a liquid Helium cryostat, where a small band gap opening was observed at 4 K temperature.

Our STEM sculpting capabilities also allow to fabricate nanoribbons with embedded nanopores, with diameters as small as 5 nm, as shown in Fig. 2. Such structure could be used for DNA sequencing purposes [2].

References [1] [2]

Q.Xu, M. Wu, G. F. Schneider, L. Houben, S.K. Malladi, C. Dekker, E. Yucelen, R.E. DuninBorkowski,and H.W. Zandbergen, ACS Nano 7 (2), 2013, pp. 1566-1572.

K.K. Saha, M. Drndić, and B. K. Nikolić, Nano Lett.,12 (1), 2012, pp 50–55

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Figures

Figure 1: STEM images of a four layer graphene sample, showing the sculpting procedure realized insitu with the microscope electron beam. Graphene is fully suspended and it is displayed in grey/white color, the empty background appears in black.

Figure 2: STEM image of a graphene ribbon, 30 nm wide, in which two nanopores were sculpted, each 5 nm in diameter.

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Terahertz Nano-detectors Exploiting Novel TwoDimensional Materials and Van der Waals Solids Miriam S. Vitiello1 and Leonardo Viti1 1 NEST, Istituto Nanoscienze – CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, I-56127, Italy

The ability to convert light into an electrical signal with high efficiencies and controllable dynamics is a major need in photonics and optoelectronics. In the Terahertz (THz) frequency range, with its exceptional application possibilities in high data rate wireless communications, security, night-vision, biomedical or video-imaging and gas sensing, detection technologies providing efficiency and sensitivity performances that can be “engineered” from scratch, remain elusive [1]. These key priorities prompted in the last decade a major surge of interdisciplinary research, encompassing the investigation of different technologies in-between optics and microwave electronics, different physical mechanisms and a large variety of material systems [1,2] offering ad-hoc properties to target the expected performance and functionalities.

The talk will provide an overview on our recent developments on THz photodetectors from graphene [1] to novel and fascinating 2D material systems, never exploited before for any active THz device, as topological insulators (TI) black-phosphorus (BP) and bi-dimensional Van der Walls heterostructures combining hexagonal borum nitride (hBN) and BP in a multistack configuration.

By exploiting the inherent electrical and thermal in-plane anisotropy of a flexible thin flake of BP, we devised plasma-wave, thermoelectric and bolometric nano-detectors with a selective, switchable and controllable operating mechanism [3,4] as well as near-field THz detection probes. All devices operates at room-temperature in the 0.3- 3.8 THz range and are integrated on-chip with planar nano-antennas, which provide remarkable efficiencies through light-harvesting in the strongly sub-wavelength device channel. The achieved selective detection (∼5-8 V/W responsivity) and sensitivity performances (signal-to-noise ratio of 500), are here exploited to demonstrate the first concrete application of a phosphorus-based active THz device, for pharmaceutical and quality control imaging of macroscopic samples, in real-time and in a realistic setting.

We furthermore combine the benefit of the heterostructure architecture with the exceptional technological potential of 2D layered nanomaterials; by reassembling the thin isolated atomic planes of hexagonal borum nitride (hBN) with a few layer phosphorene we stacked mechanically hBN/BP/hBN heterostructures layer-by-layer in a precisely chosen sequence, to devise high efficiency photodetectors operating in the 0.3-0.65 THz range from 4K to 300K with record S/N = 20000.

As a very intriguing alternative, we explored TIs which represent a novel quantum state of matter, characterized by edge or surface-states, showing up on the topological character of the bulk wave-functions. Allowing electrons to move along their surface, but not through

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their inside, they emerged as an intriguing material platform for the exploration of exotic physical phenomena, somehow resembling the graphene Dirac-cone physics, as well as for exciting applications in optoelectronics, spintronics, nanoscience, low-power electronics and quantum computing. Investigation of topological surface states (TSS) is conventionally hindered by the fact that, in most of experimental conditions, the TSS properties are mixed up with those of bulk-states. We devised a novel tool to unveil TSS and to probe related plasmonic effects. By engineering Bi2Te(3-x)Sex stoichiometry, and by gating the surface of nanoscale field-effect-transistors, exploiting thin flakes of Bi2Te2.2Se0.8 or Bi2Se3, we recently provided the first demonstration of room-temperature Terahertz (THz) detection mediated by over-damped plasma-wave oscillations on the “activated” TSS of a Bi2Te2.2Se0.8 flake [5]

References [1] [2] [3] [4] [5]

F.H.L. Koppens, T. Mueller, Ph. Avouris, A.C. Ferrari, M.S. Vitiello, and M. Polini “Photodetectors based on graphene, other twodimensional materials, and hybrid systems”, Nature Nanotech. 9, 780 (2014).

M. S. Vitiello et al. “One dimensional semiconductor nanostructures: An effective active-material for terahertz detection” APL Materials, 3, 026104 (2015).

L. Viti et al. “Black Phosphorus Terahertz photodetectors” Advanced Materials, 27, 5567 (2015).

L.Viti et al. “Efficient Terahertz detection in black-phosphorus nano-transistors with selective and controllable plasma-wave, bolometric and thermoelectric response” Scientific Reports, (2016).

L. Viti et al. “Plasma-Wave Terahertz Detection Mediated by Topological Insulators Surface States”, Nano Letters 16, 80-87 (2016).

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Electrical Characteristics of Field-Effect Transistors based on Chemically Synthesized Graphene Nanoribbons R. T. Weitz Department of Physics, LMU Munich, Germany thomas.weitz@lmu.de

Miniaturization of integrated electronic circuits down to the sub-10-nm regime requires novel semiconductors that combine high structural precision and integrity with superior and welldefined electronic properties and easy processing. Chemically synthesized graphene nanoribbons (GNRs) are ideally suited to fulfill these requirements. In our work, we show for the first time the dispersion of GNRs in aqueous solution, which is an important prerequisite for the integration of GNRs into complex electronic circuits [1]. As-fabricated GNR transistors show excellent charge injection from the metal contacts and large on-state drain currents, but a small current modulation ratio (Figure 1). The latter can be explained by the unfavorable transistor geometry or by the unintentional agglomeration of two or more GNRs in the transistor channel. Using quantum-chemical calculations we demonstrate that the band gap of a GNR dimer can be as small as 30% of the band gap of a GNR monomer (Figure 2).

References [1]

T U. Zschieschang, H. Klauk, I.B. Müller, A.J. Strudwick, T. Hintermann, M.G. Schwab, A. Narita, X. Feng. K. Müllen, and R.T. Weitz, “Electrical Characteristics of Field-Effect Transistors based on Individual Chemically Synthesized Graphene Nanoribbons”, Advanced Electronic Materials 1, 1400010 (2015)

Figures

Figure 1: (Left) Output and (right) transfer characteristics of ascontacted GNR – FET measured under ambient conditions [1].

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Figure 2: (top) possible stacking motives of GNR (bottom) calculated HOMO-LUMO gap of GNRdimers in different stacking motives [1].

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Dielectric-Graphene and Silicon-Graphene integration for Graphene-Based Devices G. Lupina1 , C. Strobel2, M. Junige2, J. Kitzmann1, M. Lukosius1, M. Albert2, J.W. Bartha2, Ch. Wenger1 1 IHP GmbH, Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany 2 Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, 01062 Dresden, Germany wenger@ihp-microelectronics.com

The integration of dielectrics or semiconductors on top of Graphene is of critical importance for the development of a new generation of Graphene-based devices, such as Graphene transistors amongst others. The deposition of a high-k dielectric, like Al2O3, or of Silicon on top of Graphene has still been challenging due to Graphene's lack of dangling bonds. In this paper, two strategies for the dielectricGraphene and Silicon-Graphene integration will be presented.

The Physical Vapor Deposition (PVD) technique has been used to directly deposit dielectric materials on Graphene but often introduced significant defects in the Graphene layer, confirmed by Raman spectroscopy and mobility measurements of top-gated Graphene transistors [1-3].

Atomic Layer Deposition (ALD) processes have been explored to deposit high-κ dielectrics on Graphene with negligible Graphene damage. However, the dielectric film nucleation has been hindered by the chemical inertness of the Graphene surface [4,5]. Therefore, the ALD growth initiation on Graphene has required a functionalization of the pristine Graphene surface with reactive groups. For example, a functionalization by Xenon difluoride (XeF2) has been found to provide additional nucleation sites resulting in conformal films without pinholes [6]. However, XeF2 is a toxic and strong oxidizing agent, which may ignite or explode on contact with combustible materials. Hence, the scope of our study was to test an alternative fluorinating agent, such as Nitrogen trifluoride (NF3), which is widely established in the microelectronics industry.

We tested the impact of NF3 pre-treatments on transferred Graphene layers prior to the ALD of Al2O3 at a substrate temperature of 400 °C. AFM revealed a substrate inhibition with a resulting island formation. Furthermore, AFM revealed that the Al2O3 morphology seemed to be improved by the NF3 pre-treatment due to an increased density of nucleation sites. As shown in Fig. 1, the pristine Graphene layer demonstrated a negligible D band as well as a proper G-to-2D intensity ratio, verifying a nearly defectfree monolayer Graphene. After the NF3 pre-treatment and the ALD coating procedure, the D band as well as the G-to-2D intensity ratio remained rather unchanged.

Using low-temperature oxidized thin e-beam evaporated aluminum as seed layer for dielectric deposition can improve the nucleation and growth resulting in closed layers.

However, methods such as the e-beam evaporation are often not compatible with large

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scale semiconductor device manufacturing. In contrast, Chemical Vapor Deposition (CVD) as well plasma enhanced CVD (PECVD) are widely accepted manufacturing methods.

PECVD is particularly interesting for applications requiring low thermal budgets such as the back end of line (BEOL) semiconductor device fabrication (< 450째C). However, high energy ion bombardment related to plasma exposure readily correlates with worsening of material properties [7,8]. Heintze et al. have demonstrated, that the ion energy in the plasma decreases with increasing frequency up to at least 180 MHz [9]. Using plasma excitation frequencies larger than 100 MHz frequencies is a unique feature in the field of PECVD methods.

We will demonstrate, that in contrast to the conventional radio frequency (RF, 13.56 MHz) PECVD a very high frequency (VHF, 140 MHz) PECVD can be used to cover CVD Graphene with thin a-Si:H layers very softly without changing the properties of the underlying Graphene significantly. Direct comparison of the RF and VHF methods demonstrated a decisive advantage of the VHF plasma: seedfree conformal coverage of Graphene at low temperatures without significant degradation of its crystalline quality. This striking difference was associated to the reduced ion energy in the VHF plasma.

An overview of Raman spectroscopy results obtained from Graphene samples covered with Si layers using RF and VHF PECVD methods is demonstrated in fig. 2. The Raman spectrum taken before Si deposition showed two strong peaks at ~ 1585 cm-1 and 2680 cm-1 which are assigned to the G and 2D bands, respectively. A negligible D band in this spectrum proved that a high quality Graphene layer was obtained after transfer. The appearance of a strong D-band (~1350 cm-1) in the spectrum taken from the RF sample clearly indicated damage of the Graphene crystalline lattice. In contrast, after the VHF PECVD process, the D band was barely visible implying a good crystalline quality of the Graphene layer was preserved.

The herein presented deposition strategies demonstrated a significant progress towards a complete fabrication scheme of Graphene-based devices in Silicon technologies.

References [1] [2] [3] [4] [5] [6] [7] [8] [9]

M. C. Lemme, T. J. Echtermeyer, M. Baus, and H. Kurz, IEEE Electron Device Lett. 28 (2007), 282.

Z. Jin, Y. Su, J. Chen, X. Liu, and D. Wu, Appl. Phys. Lett. 95 (2009), 233110.

Z. Hua Ni, H. M. Wang, Y. Ma, J. Kasim, Y. H. Wu, and Z. X. Shen, ACS Nano 2 (2008), 1033.

Y. Xuan, Y. Q. Wu, T. Shen, M. Qi, M. A. Capano, J. A. Cooper, and P. D. Ye, Appl. Phys.

Lett. 92 (2008), 013101.

F. H. Yang and R. T. Yang, Carbon 40 (2002), 437.

V. Wheeler, N. Garces, L. Nyakiti, R. Myers-Ward, G. Jernigan, J. Culbertson, C. Eddy, and D. Kurt Gaskill, Carbon 50 (2012), 2307.

M. Kondo, Y. Toyoshima, A. Matsuda and K. Ikuta, J. Appl. Phys. 80 (1996), 6061.

B. Kalache, A. Kosarev, R. Vanderhaghen and P. Roca i Cabarrocas, J. Appl. Phys. 93 (2003) 1262.

M. Heintze, R. Zedlitz Journal of Non-Cryst. Solids 198-200 (1996), 1038.

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Figures

Figure 1: Raman spectra showing G and 2D Graphene bands for as transferred Graphene after the transfer (a), after 30 TMA-H2O ALD cycles at 400 째C (b), and after 180 s NF3-pre-treatment at 400 째C and 30 TMA-H2O ALD cycles at 400 째C (c).

Figure 2: Raman spectra showing G and 2D Graphene bands for as transferred CVD Graphene and after deposition of 20 nm of amorphous Si by RF (13.56 MHz) and VHF (140 MHz) PECVD. Signal-noise ratio worsening observed after Si deposition is associated with attenuation of the Raman signal from Graphene by the Si overlayer.

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Catalytic growth of 2D carbon monolayer with controlled crystallinity: from amorphous to single-crystalline Dongmok Whang School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 16419, Korea dwhang@skku.edu

Large-area graphene has been grown by catalytic chemical vapor deposition (CVD) on various metal substrates. However, the uniform growth of defect-free single-crystal graphene over wafer-scale areas remains a challenge toward the commercial realization of various electronic, photonic, mechanical, and other devices based upon the outstanding properties of graphene. In this talk, control of crystallinity during the catalytic growth of single-atomthick 2D carbon layer will be presented. A hydrogen-terminated germanium (Ge) substrate is a promising candidate for the growth of carbon monolayer, because of (i) its reasonably good catalytic activity for the catalytic decomposition of carbon atoms on the surface, (ii) the extremely low solubility of carbon in Ge even at its melting temperature, enabling growth of complete carbon monolayer. In particular, the anisotropic atomic arrangement of single crystal Ge surface enables uniform growth of single-crystal monolayer graphene [1]. Etchfree dry transfer and possible applications of the obtained carbon monolayers will also be discussed.

References [1]

Lee, J.-H. et al. Wafer-Scale Growth of Single-Crystal Monolayer Graphene on Reusable Hydrogen-Terminated Germanium. Science 344, 286-289 (2014).

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Broadband electrical detection of propagating graphene plasmons A. Woessner1, M.B. Lundeberg1, P. Alonso-González2,3, Y. Gao4, A.Y. Nikitin2,5, A. Principi6, K. Watanabe7, T. Taniguchi7, M. Polini18, J. Hone4, R. Hillenbrand5,9, F.H.L. Koppens1,10 1 ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain 2 CIC nanoGUNE, E-20018, Donostia-San Sebastián, Spain 3 Departamento de Física, Universidad de Oviedo, Oviedo 33007, Spain 4 Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA 5 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain 6 Radboud University, Institute for Molecules and Materials, NL-6525 AJ Nijmegen, The Netherlands 7 National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan 8 Istituto Italiano di Tecnologia, Graphene labs, Via Morego 30 I-16163 Genova, Italy 9 CIC NanoGUNE and EHU/UPV, E-20018, Donostia-San Sebastian, Spain 10 ICREA – Institució Catalana de Recerça i Estudis Avancats, Barcelona, Spain achim.woessner@icfo.eu frank.koppens@icfo.eu

Controlling, detecting and generating propagating plasmons by all-electrical means is essential for on-chip nano-optical circuits. Graphene can carry long-lived plasmons that are highly confined and controllable in-situ.[1,2,3] However, electrical detection of propagating graphene plasmons has thus far not been realized.

Here, we show how high-resolution photocurrent nanoscopy can be not only applied to directly measure the charge neutrality point as well as the carrier density profile of encapsulated graphene devices in real space[4] but also to measure propagating graphene plasmons.

We present an all-graphene broadband plasmon detector. Instead of achieving detection via added optoelectronic materials, as is typically done in other plasmonic systems,[5] our device harvests the natural decay product of the Plasmon - electronic heat - and converts it directly into a voltage through the thermoelectric effect.[6,7] We use high quality graphene encapsulated between two layers of hexagonal boron nitride[8] and employ two local metal gates to fully tune the thermoelectric and plasmonic behavior. We investigate the plasmon propagation, frequency dispersion, and thermoelectric generation.

We electrically measure propagating graphene plasmons both for mid-infrared[9] and THz[10] frequencies. In the case of the THz frequency range we find that the graphene plasmon couples with the underlying metal gate. This so called graphene-insulator-metal plasmons exhibit a linear, acoustic, dispersion instead of the common square root dispersion and are strongly confined.

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This work paves the way for efficient ultra-compact detectors in both the mid-infrared and THz frequency range based on graphene plasmons as well as fully integrated graphene plasmonic circuits and THz sensors.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Z. Fei, et al., Nature 487 (2012) 82-85 J. Chen, et al., Nature 487 (2012) 77-81 A. Woessner, M.B. Lundeberg, Y. Gao, et al., Nature Materials 14 (2015) 421-425 A. Woessner, et al., accepted in Nature Communications (2016) arXiv:1508.07864 M. L. Brongersma, et al., Nature Nanotechnology 10 (2015) 25-34 F.H.L. Koppens, et al., Nature Nanotechnology 9 (2014) 780-793 M. Badioli, A. Woessner, et al., Nano Letters 14 (11) (2014) 6374-6381 L. Wang, et al., Science 342 (2013) 614-617 M.B. Lundeberg, Y. Gao, A. Woessner, et al., arXiv (2016) arXiv:1601.01977 P. Alonso-Gonzรกlez, A.Y. Nikitin, Y. Gao, A. Woessner et al., arXiv (2016) arXiv:1601.05753.

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3D Printing of Ultra-Compressible, Highly Conductive Graphene Aerogels Marcus A. Worsley1 , Cheng Zhu1 , Tianyu Liu2 , Fang Qian1 , T. Yong-Jin Han1, Joshua D. Kuntz1, Christopher Spadaccini1, Eric B. Duoss1, and Yat Li2 1 Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, United States of America 2 University of California at Santa Cruz, 1156 High St, Santa Cruz, United States of America worsley1@llnl.gov

Graphene aerogels are typically micro- and mesoporous (pores <50 nm), ultra-lighweight, conductive materials that can achieve surface areas in excess of 1000 m2 /g [1,2]. As such, they are used in a wide range of applications ranging including catalysts and catalyst supports [3,4], energy storage and conversion[5], and sorbents for water purification[6].

Aerogels are made via the sol-gel process, in which a reaction solution is gelled and the solvent is extracted in such a way as to leave the porous solid matrix intact[7]. Though their pore sizes can typically be tuned by varying the synthetic parameters of the sol-gel process [8,9], limitations do exist. For example, the tortuous, random porous network of grapheme aerogels can significantly affect supercapacitor performance by limiting ion and electron transport. Thus the fabrication of a graphene aerogel with tailored macro-architectures to facilitate mass transport via a controllable and scalable assembly method remains a significant challenge.

Here, we report the fabrication of periodic graphene aerogel microlattices for supercapacitor applications, via a 3D printing technique known as direct-ink writing (DIW) [10]. These novel grapheme structures possess an unprecedented, synthetically controlled hierarchical pore network that spans several orders of magnitude (nanometers to millimeters). (Figure 1) The key factors in developing these 3D graphene electrodes were developing an extrudable graphene-oxide (GO) based ink, and modifying the 3D printing method to accommodate aerogel processing, specifically â&#x20AC;&#x153;wet-printingâ&#x20AC;? instead of the traditional dry printing process[11]. The 3D-printed graphene aerogel electrodes are lightweight, highly conductive and exhibit excellent electrochemical properties. In particular, the supercapacitor devices using the 3D-printed electrodes with thicknesses on the order of millimeters, display capacitance retention (~90% at 10 A/g) and power densities (>4 kW/kg based on full device mass), performance which equals or exceeds that of reported devices made with electrodes 10-100 times thinner. These results highlight how the 3D printing of novel materials, such as graphene aerogels, can significantly expand the design space for fabricating complex, high performance energy storage devices that can be optimized for a broad range of applications.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and funded by the DOE Office of Energy Efficiency and Renewable Energy.

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References [1]

M. A. Worsley, P. J. Pauzauskie, T. Y. Olson, J. Biener, J. H. Satcher and T. F. Baumann, J Am Chem Soc 132 (40), 14067-14069 (2010).

[2] J. Biener, M. Stadermann, M. Suss, M. A. Worsley, M. M. Biener, K. A. Rose and T. F. Baumann, Energy Environ. Sci. 4 (3), 656-667 (2011).

[3] Z. Lin, G. H. Waller, Y. Liu, M. Liu and C.-p. Wong, Nano Energy 2 (2), 241-248 (2013).

[4] A. Harley-Trochimczyk, J. Chang, Q. Zhou, J. Dong, T. Pham, M. A. Worsley, R. Maboudian, A. Zettl and W. Mickelson, Sensor Actuat B-Chem 206, 399-406 (2015).

[5] S. Han, D. Q. Wu, S. Li, F. Zhang and X. L. Feng, Adv. Mater. 26 (6), 849-864 (2014).

[6] S. Nardecchia, D. Carriazo, M. L. Ferrer, M. C. Gutierrez and F. del Monte, Chem. Soc. Rev. 42 (2), 794- 830 (2013).

[7] J. Fricke and A. Emmerling, J. Am. Ceram. Soc. 75 (8), 2027-2036 (1992).

[8] M. A. Worsley, T. Y. Olson, J. R. I. Lee, T. M. Willey, M. H. Nielsen, S. K. Roberts, P. J. Pauzauskie, J. Biener, J. H. Satcher and T. F. Baumann, J Phys Chem Lett 2 (8), 921-925 (2011).

[9] M. A. Worsley, T. T. Pham, A. M. Yan, S. J. Shin, J. R. I. Lee, M. Bagge-Hansen, W. Mickelson and A. Zettl, Acs Nano 8 (10), 11013-11022 (2014).

[10] J. A. Lewis, Adv. Funct. Mater. 16 (17), 2193-2204 (2006).

[11] C. Zhu, T. Y. J. Han, E. B. Duoss, A. M. Golobic, J. D. Kuntz, C. M. Spadaccini and M. A. Worsley, Nat Commun 6 (2015).

Figures

Figure 1: Images of 3D-printed graphene aerogel honeycomb lattice taken at various levels of magnification using optical (left), scanning electron (middle), and transmission electron (right) microscopy.

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The Growth Mechanisms and Device Applications of Large-area MoS2 Films Prepared

by Sulfurization of Pre-deposited Molybdenum on Sapphure Substrates Chong-Rong Wu1,2, Xiang-Rui Chang2 , Tung-Wei Chu1, Chao-Hsin Wu1 and Shih-Yen Lin1,2 1 Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan 2 Research Center for Applied Science, Academia Sinica, Taipei 11529, Taiwan shihyen@gate.sinica.edu.tw

Compared with the zero-bandgap 2-D crystal, graphene, transition metal dichalcogenides (TMDs) such as MoS2 have revealed its potential for transistor applications due to the deviceâ&#x20AC;&#x2122;s high ON/OFF ratios. In nowadays, one most commonly adopted approach for large-area TMD growth is by chemical vapor deposition (CVD) [1]. Although large-area and uniform MoS2 films can be prepared by this method, the choice of suitable precursors and the incapability of selective growth are the major disadvantages of this approach. In this report, we have demonstrated large-area MoS2 growth by using sulfurization of Mo thin films predeposited on sapphire substrates in a hot furnace at 800 °C. By fixing the thickness of Mo films to 1 nm and decreasing the S powder weight, the Raman peak difference remains the similar, which suggest that the same average MoS2 layer numbers are obtained for samples grown under different S powder amounts as shown in Fig. 1 (a). With the lowest FWHM value 2.48 cm-1 corresponding to the in-plane vibration Raman peak E12g of the sample prepared with 1.5 g S power, it is demonstrated that large-area and uniform MoS2 films with high crystalline quality can be obtained by using this approach. The XPS spectrums of the MoS2 samples prepared with different amounts of S power are shown in Fig. 1 (b). With S powder amount lower than 1.5 g, the peak corresponding to the Mo-O bonding located at 236 eV is observed. The atomic ratio of S: Mo is also reduced to 1.6 for this sample, which suggests that with insufficient S, the film is not completely sulfurized such that Mo oxides would be observed. The results also indicate that the deposited Mo films will be oxidized after exposing to air. The cross-sectional HRTEM image of the sample grown with < 1.5 g S is shown in Fig. 2 (a). As shown in the figure, there are small clusters spreading over the sample surfaces. The HRTEM image with higher magnification of the same sample is shown in Fig. 2 (b). It seems that the sample surface including the small clusters is covered by few-layer MoS2. To verify the chemical compositions of the small clusters, EDX mapping of elements S and O are shown in Fig. 2 (c) and (d). As shown in the figure, it seems that the small clusters contain both elements S and O. Since the small clusters are fully covered by few-layer MoS2 as shown in Fig. 2 (b), it is possible that the S signal comes from the covering MoS2 films. In this case, it is reasonable to assume that the clusters contain mostly Mo oxides. Therefore, under S insufficient condition, the Mo oxides will undergo coalescence at first and form small clusters on the substrates. After that, sulfurization will still takes place and form few-layer MoS2 covering the sample surface. The results indicate that Mo oxides will migrate on substrate surfaces at 800 o C. Under S sufficient condition, both Mo oxides and S adatoms will migrate on the surface. Epitaxially growth of MoS2 will take place such that large-area and uniform

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MoS2 films can be obtained. The bottom-gated MoS2 transistors are fabricated by transferring the MoS2 films prepared by sulfurizing 0.2, 0.5 and 1.0 nm Mo with 1.5 g S to 300 nm SiO2/Si substrates with pre-deposited Au/Ti electrodes. The ID-VGS curves of the three devices are shown in Fig. 3. The corresponding MoS2 layer numbers are 1, 3 and 5 as shown in the HRTEM images inserted in Fig. 3. The mobility values of these three devices are 0.02, 0.07 and 0.08 cm2 /V·s, respectively. The On/Off ratios of devices increase from 3.0 × 103 , 1.2 × 104 to 2.5 × 104 with increasing MoS2 layer numbers. The results have demonstrated that multi-layer MoS2 transistors fabricated by using sulfurization of Mo films are promising for practical applications.

References [1]

C. R. Wu et. al., J. of Phys. D: Appl. Phy., 48 (2015) 435101.

Figures

Figure 1: (a) The Raman and (b) XPS spectra of the samples prepared with different S amounts.

Figure 2: 2 (a), (b) The crosssectional HRTEM images and (c), (d) EDX mappings of the sample grown with S < 1.5 g.

Figure 3: The ID-VGS curves of the three devices prepared by sulfurizing 0.2, 0.5 and 1.0 nm Mo with 1.5 g S.

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VOI-Based Valley Filter in Bilayer Graphene Yu-Shu Wu, Ning-Yuan Lue, Yen-Chun Chen, Feng-Wu Chen, Jia-Hue Jiang, and Mei-Yin Chou National Tsing-Hua University, Hsin-Chu, Taiwan yswu@ee.nthu.edu.tw

The graphene band structure exhibits two-fold valley degeneracy at the Dirac points (K and K’), giving each graphene electron the binary degree of freedom known as valley pseudospin to realize valleytronics.[1]. Gapped graphene is particularly suited to such an application, because the breaking of AB sublattice symmetry leads to the existence of a finite pseudospin magnetic moment [2], and opens the door to an electrical manipulation of valley pseudospin through the mechanism of valley-orbit interaction (VOI) that occurs between the pseudospin and an in-plane electric field. Employing a unified VOI-based methodology, we have proposed a family of electrically-controlled valleytronic devices, including valley qubits and valley FETs.[2] Here, we report the theoretical study of a recently added member of the family - a valley filtering structure consisting of a Q1D channel in bilayer graphene, with the channel defined and controlled by electrical gates as shown in Figure 1, as well as the valley valve consisting of two of the proposed filters which can perform a two-way conversion between electrical and valleytronic signals as shown in Figure 2. We discuss two types of calculations – those of the Q1D energy subband structure in the channel of a filter and the electron transmission through a valley valve. For the former, we have developed a tight binding formulation in the continuum limit, which yields the energy subband structure shown in Figure 3 and the corresponding valley polarization of a subband state shown in Figure 4. For the calculation of electron transmission through a valley valve, we employ the recursive Green’s function method, and consider two configurations of in-plane fields in the filters as shown in Figure 5, with the result shown in Figure 6 demonstrating the potential of the valve to function as an electrically controlled on-off switch. The results will be discussed in the presentation.

References [1] [2] [3]

Rycerz et al., Nat. Phys. 3 (2007),172.

Xiao et al., Phys. Rev. Lett. 99, (2007), 236809.

Wu et al., Phys. Rev. B 84, (2011), 195463; ibid B 86 (2012), 045456; ibid B 86 (2012), 165411; ibid B 88 (2013), 125422.

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Figure 4

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Initiative of Graphene Commercialization in China Xiaoyue Xiao, Yichun Li, Zhaoping Liu China Innovation Alliance of the Graphene Industry, A-1226, Center for International Technology Transfer, 3 Haidian Ave, Haidian, Beijing, China 100083 sxiao@syfsci.com; liyichun0105@163.com; liuzp@nimte.ac.cn

In November 30 of 2015, the Ministry of Industry and Information Technology, the National Development and Reform Commission, and the Ministry of Science and Technology issued an official document: [Guidance on Graphene Industrial Innovation and Development] [1], to speed up grapheme commercialization in China.

This document was based on the status of graphene industrialization in China, and was succeeded from the 12-5 plan stated in the documents of [Development Projects of the National Strategic New Industries in the 12-5 Plan] [2] and [Made in China 2025 ] [3] issued by the State Council, [12-5 Development Planning of New Materials Industries] [4] and [2015 Key Working Points of Transformation Development of Raw Materials Industries] [5] issued by the Ministry of Industry and Information Technology, and [Embodiment of Updating and Upgrading Projects of Key Materials Technology] [6] issued by the National Development and Reform Commission etc.

The key points of this guidance are summarized below: 1. Seize the opportunity of the rising period of graphene industrialization: The guidance indicates that it is the critical time for graphene technology moving up from R&D to industrialization.

2. Build graphene technology as the forerunner industry: a. To 2018, the production chain of graphene manufacture, downstream R&D, and commercial products shall be built up. b. To 2020, well established graphene manufacture and marketing system shall be completed. This includes about 10 strong competitive companies that can manufacture standardized graphene products with competitive prices, and 3 â&#x20AC;&#x201C; 5 world leading innovation platforms.

3. Drive key technology innovation: a. Solve problems in processing, ensure controllable product quality and processing stability. b. Secure IP system. c. Establish public service system including analytical laboratories and quality control platforms.

4. Promote exemplary of downstream applications: a. Focus on energy storage devices, functional coatings, re-enforced rubber and tires, thermal management products, sensors, touching components, and electronic components etc. b. From 2016 to 2018, build up 12 exemplary production lines for commercialization of graphene applications, i.e., 4 lines per year.

5. Develop green and recyclable processing, and ensure sustainable development.

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6. Serve for the national key engineering projects and for continuous improvement of life quality.

7. Supporting systems include privilege policy made by the governments, oriented investment, standardization system, and other necessary supportive services.

Overall, it emphasizes the importance of international cooperation in graphene commercialization.

References [1]

[2] [3] [4] [5]

[6]

http://www.miit.gov.cn/n1146285/n1146352/n3054355/n3057569/n3057581/c4471155/ content.html 《关于加快石墨烯产业创新发展的若干意见》，工信部联原〔2015〕435 号。 http://www.gov.cn/zwgk/2012-07/20/content_2187770.htm 《“十二五”国家战略性新兴产业发展规划》，国发〔2012〕28 号。 http://www.mof.gov.cn/zhengwuxinxi/zhengcefabu/201505/t20150519_1233751.htm 《中国制造 2025》，国发〔2015〕28 号。 http://www.miit.gov.cn/n11293472/n11293832/n11293907/n11368223/14470388.html 《新材料产业“十二五”发展规划》。 http://www.miit.gov.cn/n1146285/n1146352/n3054355/n3057569/n3057573/c3570875/ content.html 《2015 年原材料工业转型发展工作要点》，工信厅原函[2015]106 号。 http://www.miit.gov.cn/n11293472/n11293832/n11293907/n11368223/16220076.html 《关键材料升级换代工程实施方案》， 发改高技[2014]2360 号。

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Homo-junction tunneling transistors formed with chemically doped two-dimensional materials Won Jong Yoo, Daeyeong Lee, Youngdae Jang, Jaehwan Kweon, Xiaochi Liu and Min Sup Choi Department of Nano Science and Technology, Sungkyunkwan University, Suwon, Korea yoowj@skku.edu

Two-dimensional (2D) crystals are intensively being studied because of their great potential to be an ultrathin body to realize efficient electrostatic modulation which can enable low voltage semiconductor device operation [1]. Their potential to be an ultrathin body further offers an advantage to result in high quantum tunneling current, since tunneling distance of charge carriers can be significantly reduced when p-n junctions are formed in 2D layered structured crystals. Therefore, 2D structured devices can present a significant advantage in the development of tunneling transistor technology [2] by overcoming the low on-current issue. In this work, we present various results on materials and electrical properties which were obtained from the homogeneous p+-n+ junctions which were fabricated by differentially doping few-layer 2D crystals by chemical surface treatments [3,4]. Interestingly, we present negative differential resistance observed at room temperature, by using the tunneling devices fabricated with few layer 2D crystals of molybdenum disulfide (MoS2) and block phosphorous (BP).

References [1] [2] [3] [4]

Hua-Min Li, Daeyeong Lee, Deshun Qu, Xiaochi Liu, Jungjin Ryu, Alan Seabaugh, and Won Jong Yoo, Ultimate thin vertical pâ&#x20AC;&#x201C;n junction composed of two-dimensional layered molybdenum disulfide, Nat. Commun. 6, 7564 (2015) L. Hao and A. Seabaugh, A. Tunnel Field-Effect Transistors: Stateof-the-Art. IEEE J. Electron Devices Soc. 2, 44â&#x20AC;&#x201C;49. (2014) Sung Kim, Dong Hee Shin, Chang Oh Kim, Soo Seok Kang, Jong Min Kim, Chan Wook Jang, Soong Sin Joo, Jae Sung Lee, Ju Hwan Kim, Suk-Ho Choi, and Euyheon Hwang, Graphene p_n Vertical Tunneling Diodes, 7, 5168, (2013) Seung Hwan Lee,Min Sup Choi, Jia Lee, Chang Ho Ra, Xiaochi Liu, Euyheon Hwang, Jun Hee Choi, Jianqiang Zhong, Wei Chen, and Won Jong Yoo, High performance vertical tunneling diodes using graphene/hexagonal boron nitride/graphene heterostructure, Appl. Phy. Lett. 104, 053103 (2014).

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Mesoscopic Modeling of 2D Materials Shengjun Yuan Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, NL-6525AJ Nijmegen, the Netherlands s.yuan@science.ru.nl

Detailed understanding of the electronic, transport and optical properties of 2D materials requires the study of systems crossing over from microscopic to mesoscopic. New quantum phenomena emerge in mesoscopic structures, such as interference effects, quantum confinement effects, and charging effects. The ab initio calculations, including density functional theory and its extensions such as the GW-approximation and time-dependent DFT, are powerful tools for systems up to thousands of atoms, but become too computationally expensive and time-consuming with increasing system size. For structures with scales larger than 100 nanometers, such approaches are unfeasible.

Tight-binding propagation methods (TBPMs) [1-5] are a set of new numerical methods for the modeling of systems range from microscopic to mesoscopic level. TBPMs are based on the wave propagation of electron according to the time-dependent Schrรถdinger equation, and applied in the calculations of various properties, including but not limited to density of states, quasieigenstates, static and dynamic (optical) conductivity, polarization function, dielectric function, energy loss function, plasmon damping rate, diffusion coefficients, mean free path, localization length, electron velocity and mobility, magnetic susceptibility, and tunneling probability. The magnetic field is introduced by means of the Peierls substitution and the effect of electron-electron interaction is considered within the random phase approximation.

The computational effort of the calculation increases only linearly with the system size, which makes the methods extremely powerful in the mesoscopic simulation with detailed atomic structure, especially in systems where the translational invariance does not hold, for example, the presence of random or correlated disorders or structures.

In this talk, I will first give a brief introduction of the numerical methods, and then show their applications together with our very recent progresses in the study of 2D materials, such as the reduced optical gap in fluorographene due to various structure disorders [6] (Figure 1), many-body enhancement of insulating states at the additional Dirac points in graphene-hBN heterostructures [7] (Figure 2), effects of disorder in the electronic and optical properties of semiconducting black phosphorus [8-9] and transition metal dichalcogenides [10], a new tight-binding model parametrization for black phosphorus with an arbitrary number of layers [11], quantum Hall effects in biased black phosphorus [12], and conductance fluctuations in novel 2D fractals [13]. I will also show how to combine the TBPMs with other well-known numerical methods such as DFT-GW and molecular dynamics, and discuss briefly possible extension of TBPMs to the study of many-body problem.

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References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

S. Yuan, H. De Raedt, and M. I. Katsnelson, Phys. Rev. B, 82 (2010)115448.

T. O. Wehling, S. Yuan, A. I. Lichtenstein, A. K. Geim, and M. I. Katsnelson, Phys. Rev. Lett., 105 (2010) 056802.

S. Yuan, R. Roldรกn, and M. I. Katsnelson, Phys. Rev. B, 84 (2011) 035439.

S. Yuan, T. O. Wehling, A. I. Lichtenstein, and M. I. Katsnelson, Phys. Rev. Lett., 109 (2012) 156601.

R. Logemann, K. J. A. Reijnders, T. Tudorovskiy, M. I. Katsnelson, and S. Yuan*, Phys.

Rev. B, 91 (2015) 045420.

S. Yuan, M. Rosner, A. Schulz, T. O. Wehling, M. I. Katsnelson, Phys. Rev. Lett., 114 (2015) 047403.

G. J. Slotman, M. M. van Wijk, P. -L. Zhao, A. Fasolino, M. I. Katsnelson, S. Yuan*, Phys.

Rev. Lett., 115 (2015) 186801.

F. Jin, R. Roldรกn, M. I. Katsnelson, S. Yuan*, Phys. Rev. B, 92 (2015) 115440.

S. Yuan, A. N. Rudenko, M. I. Katsnelson, Phys. Rev. B, 91 (2015) 115436.

S. Yuan, R. Roldรกn, M. I. Katsnelson and F. Guinea, Phys. Rev. B, 90 (2014) 041402(R).

A. N. Rudenko, S. Yuan, M. I. Katsnelson, Phys. Rev. B, 92 (2015) 085419.

S. Yuan, M. I. Katsnelson, R. Roldรกn, arXiv:1512.06345 (2015).

E. van Veen, A. Tomadin, M. I. Katsnelson, S. Yuan*, and M. Polini, arXiv:1504.00628 (2015).

Figures

Figure 1: Optical conductivity of fluorographene (CF) with various structure disorders.

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Figure 2: Transport property of graphene on top of hBN. The additional Dirac point on the hole side becomes insulating when considering the many-body enhancement of the local gap between the sublattices, which is clarified by ď &#x201E;U. The numerical results reproduce the transport measurements of graphene/hBN heterostructure performed by L. A. Ponomarenko, et al, in Nature 497, 594 (2013).

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Metallic nanoislands on graphene as highly sensitive transducers of mechanical, biological, and optical signals Aliaksandr V. Zaretski, Samuel E. Root, Alexander Savtchenko, Elena Molokanova, Adam D. Printz, Liban Jibril, Gaurav Arya, Mark Mercola, and Darren J. Lipomi Department of NanoEngineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0448, USA azaretsk@ucsd.edu

This work describes an effect based on the wetting transparency of graphene: the morphology of a metallic film (≤20 nm) when deposited on graphene by evaporation depends strongly on the identity of the substrate supporting the graphene. This control permits the formation of a range of geometries: tightly packed nanospheres, nanocrystals, and island-like formations with controllable gaps down to 3 nm. These graphenesupported structures can be transferred to any surface and function as ultra-sensitive mechanical signal transducers with high sensitivity and range (at least four orders of magnitude of strain) for applications in structural health monitoring, electronic skin, measurement of the contractions of cardiomyocytes, and substrates for surface-enhanced Raman scattering (SERS, including on the tips of optical fibers). These composite films can thus be treated as a platform technology for multimodal sensing. Moreover, they are low profile, mechanically robust, semitransparent, and have the potential for reproducible manufacturing over large areas.

References [1] [2] [3] [4] [5] [6]

Bae, S. et al. Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nat. Nanotechnol. 5, 574–8 (2010).

Hao, Y. et al. The Role of Surface Oxygen in the Growth of Large Single-Crystal Graphene on Copper. Sci. 342 , 720–723 (2013).

Rafiee, J. et al. Wetting transparency of graphene. Nat. Mater. 11, 217–222 (2012).

Regmi, M., Chisholm, M. F. & Eres, G. The effect of growth parameters on the intrinsic properties of large-area single layer graphene grown by chemical vapour deposition on Cu. Carbon N. Y. 50, 134–141 (2012).

Zaretski, A. V et al. Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates. Nanotechnology 26, 45301 (2015).

Ohring, M. Materials Science of Thin Films. Mater. Sci. (2001). doi:10.1016/B978012524975-1/50010-0.

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Figures

Figure 1: Schematic diagram of the process used to generate nanoislands (top) and scanning electron micrographs of metallic nanoislands on various substrates obtained by electron beam evaporation of evaporant (y-axis) onto a graphene/metal substrate (x-axis) (bottom). 10 nm of gold (first row) and 10 nm of silver (second row) evaporated onto (left to right): graphene on copper foil (as grown), MAEtransferred graphene on nickel, MAE-transferred graphene on gold, MAE-transferred graphene on silver. Each evaporant was deposited onto the substrates concurrently in the same chamber. Scale bars: 200 nm. Scale bars in insets: 50 nm.

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Figure 2: Nanoisland strain sensors. a, Photograph of the PDMS/PdNI/graphene strain sensor placed atop the radial artery for detection of the pulse (overlaid in figure). Note the high resolution of the pulse pressure-waveform (in the blow-out) with distinguishable systolic and diastolic pressures, the dicrotic notch (aortic valve closure), and other cardiac cycle events. b, Normalized resistance plot of the PDMS/graphene/PdNI strain sensor stretched cyclically (20 cycles for each strain) to 1, 2, 3, …

9% strain. c, Schematic diagram of a graphene/PdNI strain sensor used to sense 0.001% tensile strain on the surface of the 130 µm-thick glass coverslip (used as a cantilever with the amplitude of deflection equal to 13 µm). Finite-element analysis (FEA) model of the strain on the cantilever surface (left inset). Normalized resistance plot of the graphene/PdNI strain sensor under cyclic tensile strain of 0.001% (right inset). d, Scanning electron micrograph of the glass/graphene/PdNI strain sensor under tensile strain of ~0.001%. Scale bar: 100 nm. Scale bar in inset: 25 nm. e, Scanning electron micrograph of the PDMS/graphene/PdNI strain sensor under tensile strain of ~3%. Scale bar: 100 nm.

Scale bar in inset: 25 nm

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Synthesis and Applications of Novel TwoDimensional Nanomaterials Hua Zhang School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore http://www.ntu.edu.sg/home/hzhang/ HZhang@ntu.edu.sg

In this talk, I will summarize the recent research on synthesis, characterization and applications of twodimensional nanomaterials in my group. I will introduce the synthesis and characterization of novel lowdimensional nanomaterials, such as graphene-based composites including the first-time synthesized hexagonal-close packed (hcp) Au nanosheets (AuSSs) on graphene oxide, surface-induced phase transformation of AuSSs from hcp to face-centered cubic (fcc) structures, the synthesis of ultrathin fcc Au@Pt and Au@Pd rhombic nanoplates through the epitaxial growth of Pt and Pd on the hcp AuSSs, respectively, the first-time synthesis of 4H hexagonal phase Au nanoribbons (NRBs) and their phase transformation to fcc Au RNBs as well as the epitaxial growth of Ag, Pt and Pd on 4H Au NRBs to form the 4H/fcc Au@Ag, Au@Pt and Au@Pd coreâ&#x20AC;&#x201C;shell NRBs, and the epitaxial growth of metal and semiconductor nanostructures on solution-processable transition metal dichalcogenide (TMD) nanoshees at ambient conditions, single- or few-layer metal dichalcogenide nanosheets and hybrid nanomaterials, the large-amount, uniform, ultrathin metal sulfide and selenide nanocrystals, other 2D nanomaterials, nanodots prepared from 2D nanomaterials, and self-assembled 2D nanosheets and chiral nanofibers from ultrathin lowdimensional nanomaterials. Then I will demonstrate the applications of these novel nanomaterials in chemical and bio-sensors, solar cells, water splitting, hydrogen evolution reaction, electric devices, memory devices, conductive electrodes, other clean energy, etc.

314

April 19-22, 2016 Genoa (Italy)

Graphene2016

Lighting up the Raman Signal of Molecules in the Vicinity of Graphene Related Materials Jin Zhang Center for Nanochemistry, College of Chemistry and Molecular Engineering, Peking University, China jinzhang@pku.edu.cn

Surface enhanced Raman scattering (SERS) is a popular technique to detect the molecules with high selectivity and sensitivity. Nevertheless, how to make the SERS signals repeatable and quantitative, and how to understand the chemical enhancement mechanism are still big challenges. Recently, graphene, as well as the other two dimensional (2D) materials, were developed to be used as a Raman enhancement substrate, which can light up the Raman signals of molecules, and these substrates were demonstrated to be a promising for micro/trace species detection. In this talk, the multi-role of graphene and its related materials played in SERS is overviewed in turn, including a Raman probe, a substrate, an additive and a building block of a flat surface for SERS.

References [1]

J Zhang et. al., Lighting Up the Raman Signal of Molecules in the Vicinity of Graphene Related Materials, Acc. Chem. Res. 48 (7) (2015), 1862-1870.

Figures

Graphene Enhanced Raman Scattering (GERS)

Figure 1: Graphene Enhanced Raman Scattering (GERS).

Graphene2016

April 19-22, 2016 Genoa (Italy)

315

A two-dimensional Dirac material on a band gap substrate: Germanene on MoS2 L. Zhang1, P. Bampoulis1, A.N. Rudenko2, Q. Yao1, A. van Houselt1, B. Poelsema1, M.I. Katsnelson2 and H.J.W. Zandvliet1 1 Physics of Interfaces and Nanomaterials group, MESA+ Institute for Nanotechnology and University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands 2 Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands l.zhang@utwente.nl

To date germanene has only been synthesized on metallic substrates [1-3]. A metallic substrate is usually detrimental for the two-dimensional Dirac nature of germanene because the important electronic states near the Fermi level of germanene can hybridize with the electronic states of the metallic substrate. Here we report the successful synthesis of germanene on molybdenum disulfide (MoS2), a band gap material. Pre-existing defects in the MoS2 surface act as preferential nucleation sites for the germanene islands. The lattice constant of the germanene layer (3.80.2 Å) is about 20% larger than the lattice constant of the MoS2 substrate (3.16 Å). Scanning tunneling spectroscopy measurements performed on the virtually continuous germanene layers reveal a V-shaped density of states, which is a clear hallmark of a two-dimensional Dirac material. These experimental results are in very good agreement with density functional theory calculations.

References [1] [2] [3]

P. Bampoulis, L. Zhang, A. Safaei, R. Van Gastel, B. Poelsema, H.J.W Zandvliet, J. Phys.

Cond. Mat. 26 (2014) 442001.

L. Zhang, P. Bampoulis, A. van Houselt, H.J.W Zandvliet, Appl. Phys. Lett.

107(2015)111605.

A. Acun, L. Zhang, P. Bampoulis, M. Farmanbar, A. van Houselt, A.N. Rudenko, M. Lingenfelder, G. Brocks, B. Poelsema, M.I. Katsnelson, H.J.W. Zandvliet, J. Phys. Cond.

Mat. 27(2015)44300

316

April 19-22, 2016 Genoa (Italy)

Graphene2016

Figures

Figure 1: a). Scanning tunneling microscopy image of the MoS 2/germanium substrate. The sample bias is 0.5 V and the tunneling current is 0.3 nA. b). A zoom-in on a bare MoS2 area. The STM image reveals a honeycomb structure with a lattice constant of 3.15 ± 0.2 Å, which corresponds to the lattice constant of MoS2. The sample bias and the tunneling current are the same as in (a) c). A zoom-in on the large germanene island of figure (a) reveals a hexagonal lattice with a lattice constant of 3.8 ± 0.2 Å. The sample bias and the tunneling current are the same as in (a).

Graphene2016

April 19-22, 2016 Genoa (Italy)

317

Nanocomposites from Polyethylene Glycol Modified Graphene and Transferrin as Highly Targeted Antitumor Drug Carriers Bingxin Zhao, Mimi Lin, Lu Yan, Wenjing Zhang, Yong Liu* Lab. of Nanoscale Biosensing and Bioimaging, School of Ophthalmology and Optometry, Wenzhou Medical University. 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027, China yongliu1980@hotmail.com

We present our recent efforts on synthesis of nanocomposites from polyethylene glycol (PEG) modified graphene incorporated with Transferring (Tf) and their application in drug delivery. Pegylated graphene (PG) was prepared using a facile but efficient technique: the edge-functionalized ball milling (EFBM) method. PEG will edge-functionalized the graphite layers during the initial step of ball milling. Exfoliation of graphene nanosheets can be realized by expanding the layered spaces with increasing PEG chains and ball milling shear forces. The resulting PG provides additional advantages for drug delivery including unique size and huge surface areas arising from graphene, and excellent biocompatibility, hydrophilicity and pH sensitivity with the addition of PEG. Tf was further introduced into the PG via a facile amidation process to enhance targeted ability of the resulting nanocarriers.

Anticancer drug e.g. doxorubicin (DOX) was subsequently encapsulated in the PEG-Tf for suppression of tumor cells such as the typical choroidal melanoma cell line: OCM-1 cell.

Atomic forace microscopy confirmed that the thickness of the as-synthesized PG was around 1.3 nm. DO loading ratio at the PG and PG-Tf were found to be 58% and 50% respectively, much higher than the general drug delivery system. The targeting and suppression ability of PG-Tf-DOX towards OCM-1 cells were determined by the Transwell coculture technique and the CCK-8 assay respectively. Much lower cell viability of OCM-1 cells than that of ARPE-19 cells was obtained when cells were co-cultured with PG-Tf-DOX, confirming the superb targeting ability of PEG-Tf-DOX towards OCM-1 cells. A 3D cell culture model was further used to simulate the antitumor effects. The changed volumes of simulating solid tumor demonstrated that PG-Tf-DOX had an excellent antitumor effect.

Release of DOX from the PG-Tf exhibited a highly pH-sensitivity. Much faster release in acidic solution (tumor environment) was observed, suggesting great possibility of the controlled release of DOX from the PG-Tf-DOX at the tumor environment.

318

April 19-22, 2016 Genoa (Italy)

Graphene2016

Graphene-Coupled Sandwich-like Porous Polymers for Energy Storage and Conversion Xiaodong Zhuang*, Xinliang Feng Dresden University of Technology, Mommsenstr. 4, 01069 Dresden, Germany xiaodong.zhuang@tu-dresden.de

Porous polymers have attracted tremendous attention because of their porous features associated with prominent physicochemical properties and vast potential energy-related applications. We have focused on the design and synthesis of microporous polymers, which are famous for efficient synthesis with various functional monomers and adaptable properties. In order to obtain the perfect and robust porous structure, utilizing graphene as template is an excellent approach for the inspired construction of 2D porous nanohybrid materials. Furthermore, it is convenient to transfer into porous carbon structure with continuous networks by direct pyrolysis. The designed 2D polymers/carbons possess rich pore structures, high surface areas, and excellent electrical conductivity. Therefore, graphene coupled 2D porous polymers can exhibit multiple functions and novel applications. Most recent progress about this topic will be presented.

References [1] [2] [3] [4] [5] [6] [7] [8] [9]

X. Zhuang, F. Zhang, D. Wu, N. Forler, H. Liang, M. Wagner, D. Gehrig, M. R. Hansen, F. Laquai, X. Feng, Angew. Chem. Int. Ed. 2013, 52, 9668-9672.

X. Zhuang, F. Zhang, D. Wu, X. Feng, Adv. Mater. 2014, 26, 3081-3086.

S. Han, Y. Feng, F. Zhang, C. Yang, Z. Yao, W. Zhao, F. Qiu, L. Yang, Y. Yao, X. Zhuang, X. Feng, Adv. Funct. Mater. 2015, 25, 3899-3906.

X. Zhuang, D. Gehrig, N. Forler, H. Liang, M. Wagner, M. R. Hansen, F. Laquai, F. Zhang, X. Feng, Adv. Mater. 2015, 27, 3789-3796.

Y. Su, Y. Liu, P. Liu, D. Wu, X. Zhuang, F. Zhang, X. Feng, Angew. Chem. Int. Ed. 2015, 54, 1812-1816.

W. Zhao, Z. Hou, Z. Yao, X. Zhuang, F. Zhang, X. Feng, Polym. Chem. 2015, 6, 7171â&#x20AC;&#x201C; 7178.

S. Sfaelou, X. Zhuang, X. Feng, P. Lianos, RSC Advances 2015, 5, 27953-27963.

X. Yang, X. Zhuang, Y. Huang, J. Jiang, H. Tian, D. Wu, F. Zhang, Y. Mai, X. Feng, Polym.

Chem. 2015, 6, 1088-1095.

K. Yuan, X. Zhuang, H. Fu, G. Brunklaus, M. Forster, Y. Chen, X. Feng, U. Scherf, 2016, submitted.

Graphene2016

April 19-22, 2016 Genoa (Italy)

319

Figures

320

April 19-22, 2016 Genoa (Italy)

Graphene2016

Graphene field-effect biosensors for real-time label-free binding kinetics Laura Zuccaro1,2, Birgitta Knudsen3,4, Alessandro Desideri2, Klaus Kern1,5 and Kannan Balasubramanian1 1 Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany 2 Department of Biology, University of Rome Tor Vergata, I-00133 Rome, Italy 3 Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark 4 Interdisciplinary Nanoscience Center (iNANO), DK-8000 Aarhus, Denmark 5 Institut de Physique de la Matiere Condensee, EPFL, CH-1015 Lausanne, Switzerland l.zuccaro@fkf.mpg.de

Electronic devices based on single nanostructures show high promise for applications in biosensing. Field-effect sensors permit the direct label-free detection of the analyte without the need for additional reactions, through the monitoring of changes in the electrical characteristics. In addition, nanoscale fieldeffect devices allow for high sensitivity, enabling the detection of very low concentrations of target analytes [1]. Besides the sensitivity, the selectivity towards a target molecule is another important aspect in the realization of a sensor. In order to provide high selectivity, it is necessary to have a clear understanding of the electrostatic and biochemical properties at the sensor surface. In the talk, we present results pertaining to the charge-potential landscape at the graphene-liquid interface, obtained systematically using field-effect measurements performed in liquid. This enables us to estimate the isoelectric point (pI) or point of zero charge (pzc) of graphene surface [2]. By electrochemical functionalization we decorate bare graphene with a varying density of aromatic molecules and demonstrate that the pI/pzc can be modulated for the application of interest.

Following this, we present a field-effect device for the real-time measurements of the activity of the enzyme human topoisomerase I with its substrate molecules [3]. For this purpose, the impedance of the device is continuously monitored as a function of the gate voltage, applied through an Ag/AgCl reference electrode in contact with the liquid. By monitoring the changes in the transfer characteristics of the device, we can follow the interaction of the enzyme with its DNA substrate in real-time, and we can extract information about the binding kinetics at picomolar concentrations. The results obtained are highly promising for the use of liquid-gated graphene biosensors for the detection of the activity of a wide number of enzymes and for the analysis of the kinetics of various binding interactions.

References [1] [2] [3]

Kurkina T. et al. Angew Chem Int Ed Engl. 50 (2011) 3710 Zuccaro L. et al. Sci Rep. 5 (2015) 11794 Zuccaro L. et al. ACS Nano 9 (11) (2015) 11166.

Graphene2016

April 19-22, 2016 Genoa (Italy)

321

Semi-automated delamination of CVD-grown graphene in Your own lab Krzysztof ZwoliĹ&#x201E;ski Nano Carbon, Poland

Doing graphene transfer in Your lab gives You several advantages over competitors. Of course, it would be even better to produce graphene on Your site, but it takes some time and money to learn how to do. Not everybody is willing to afford that, are You? During the presentation Krzysztof ZwoliĹ&#x201E;ski will explain benefits of running own CVD grapheme transfer lab and discuss basic equipment to do it on site. One of them is semi-automated system for electrochemical delamination of graphene, a new commercial product from Nano Carbon.

Delaminator allows user to move the sample (i.e. graphene on copper covered with polymer) torwards the electrolyte at controlled speed and current flow.

Figures

322

April 19-22, 2016 Genoa (Italy)

Graphene2016

P

OSTERS LIST

P

osters list: a lph abet ic al orde r

Only Posters submitted by fully registered participants are listed below: 270 (as of 05/04/2016)

authors Mohsen Aadeli Rainer Haag

Leili Abdollahi Shiramin Dries Van Thourhout

country

topic

poster title

Germany

Chemistry of 2D materials

Zwitterionic Graphene Sheets with the Switchable Bacterial Interactions

Belgium

Theory and Simulation

Broadband Double layer Graphene Switch Integrated on Silicon and Silicon Nitride Waveguide

Denmark

Theory and Simulation

Graphene nanoribbons with sublattice-asymmetric doping

Canada

Chemistry of 2D materials

Graphene dispersions in alkanes: toward fast drying conducting inks

Italy

Growth, synthesis techniques and integration methods

Multilayer graphene on SiC(000-1): thermal decomposition versus chemical vapor deposition

Spain

Chemistry of 2D materials

Effect of thermal treatment on the electrical and thermal conductivity of the graphene oxide

Spain

Chemistry of 2D materials

Chemical Bonding of Transition-metal Co13 Clusters with Graphene

Canada

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Changing in Sensing Mechanism of Graphene Oxide Gel Photodetector

Italy

Theory and Simulation

Fracture patterns of graphene sheets under ballistic penetration

Thomas Aktor Antti-Pekka Jauho and Stephen R. Power

Ahmad Al Shboul JĂŠrome Claverie

Ameer Al-Temimy D. Convertino, M. Al-Ahmad, H. Benia, U. Starke and C. Coletti

Beatriz Alonso Amaya Ortega, Jamal Tallal, Ruben Salgado, Hoda Malekpour, Alexander Balandin and Amaia Zurutuza

TomĂĄs Alonso-Lanza A. Ayuela and F Aguilera-Granja

Dawood Alsaedi Khaled M. Ibrahim, Mehrdad Irannejad, K.P. Mussleman, Mustafa Yavuz, Omar Ramahi

Rafael Amatte Bizao L. D. Machado, J. M. de Sousa, Nicola M. Pugno, Douglas S. Galvao

authors

country

Takashi Aoyama R. Hoki, S.Yamauchi, T. Komiyama, Y.Chonan, and H.Yamaguchi

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Schottky-barrier heights for metal/graphene/ZnO hetero-junctions by direct bonding technique

Austria

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Analysis of graphene-hBN heterostructures by high-resolution scanning transmission electron microscopy with direction-sensitive detection of scattered electrons

Spain

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Heat transport in two-dimensional heterostructures studied using Raman thermometry

Italy

Chemistry of 2D materials

Graphene and reduced graphene oxide based coatings to improve moisture barrier performance of PET bottles.

Myanmar

Growth, synthesis techniques and integration methods

Synthesis of graphene on copper using chemical vapor deposition

Denmark

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Tunable bandgap in graphene induced by well-ordered H structures

Spain

Theory and Simulation

Hydrogen physisorption and intercalation in novel nano-porous graphites

Germany

Growth, synthesis techniques and integration methods

Effect of growth rate and growth mechanism on the shape of graphene grains in a 4” CVD reactor

Italy

Composites for Energy applications

Supramolecular Hybrids of Thioethylporphyrazine with Graphene and Carbon Nanotubes for Photoinduced Electron Transfer

Italy

Chemistry of 2D materials

Scalable methodology for the direct synthesis of atomically thin WS2 films

Italy

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Coherent absorption of light by graphene and other optical conducting surfaces in realistic on-substrate configurations

Spain

Theory and Simulation

Defect Fingerprints and Reactivity by Ab Initio-based STM and AFM Simulations in Single Layer MoS2

Alois Arrighi J.S. Reparaz, Z. Messele, C.M. Sotomayor Torres, and S. O. Valenzuela

Chiara Ascione Nay Soe Aung Myint Naing Oo, Zaw Tun Lwin, Win Soe

Richard Balog J. Jorgensen, A. G. Cabo, M. Bianchi, P. Hofmann and L. Hornekær

Massimiliano Bartolomei Estela Carmona-Novillo, Giacomo Giorgi

Bilge Bekdüz Johanna Meier, Yannick Beckmann, Wolfgang Mertin, Gerd Bacher

Sandra Belviso E. Santoro, F. Lelj, A. Capasso, L. Najafi, A. E. Del Rio Castillo, S. Casaluci, T. M. Brown, A. Di Carlo, F. Bonaccorso

poster title

Japan

Giacomo Argentero A. Mittelberger, C. Yang, J. Kotakoski, C. Mangler, T. Pennycook, C. Kramberger, A. K. Geim, J. C. Meyer

topic

Giuseppe Valerio Bianco Maria Losurdo, Maria Michela Giangregorio, Alberto Sacchetti, Pio Capezzuto, Giovanni Bruno

Federica Bianco S. Zanotto, V. Miseikis, D. Convertino, C. Coletti, A. Tredicucci

Blanca Biel César González, Yannick Dappe

authors

country

topic

Axel Blau Asiyeh Golabchi, Rouhollah Habibey and Ilker S. Bayer

poster title

Italy

Health and Medical Applications

Biocompatibility and conductivity of flexible graphene electrodes for neural electrophysiology

Slovakia

Health and Medical Applications

Confocal Raman spectroscopy study of intracellular localization of graphene oxide nanoplatform under development for targeted delivery to cancer cells

Italy

Health and Medical Applications

Graphene Oxide disrupts lipid composition, Ca2+ homeostasis and synaptic transmission in primary cortical neurons, without affecting neuronal survival and excitability

New Zealand

Chemistry of 2D materials

Capacitance of Few-Layer Graphene Electrodes Modified by Spontaneous Aryldiazonium Chemistry

Italy

Theory and Simulation

Planetary Ball Milling Model for optimal 2-D Materials Exfoliation

Belgium

Chemistry of 2D materials

Covalent modification of graphene and graphite using diazonium chemistry: tunable grafting and nano-manipulation

Germany

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Photophysical interaction of liquid-phase exfoliated graphite with zinc phthalocyanines in aqueous solution and methanol

Poland

Theory and Simulation

Analysis of symmetry in the graphene quantum dots with different edges

Russia

Photonics and Plasmonics

Quantum-cascade photon gain in tunnel-coupled graphene layers

Australia

Chemistry of 2D materials

Molecule-Induced Conformational Change in Two-Dimensional Nanomaterials with Enhanced Surface Adsorption

Michal Bodik Marianna Sohová, Peter Šiffalovic, Matej Jergel, Tibor Hianik, Nikola Bugárová, Zdeno Špitálsky, Mária Omastová, Martina Labudová, Silvia Pastoreková and Eva Majková

Mattia Bramini Silvio Sacchetti, Andrea Armirotti, Ester Vázquez, Verónica León Castellanos, Tiziano Bandiera, Fabrizia Cesca and Fabio Benfenati

Paula A. Brooksby Anna K. Farquhar, Alison J. Downard

Marica Broseghini L. Gelisio, M. D'Incau, N. Pugno & P. Scardi

Anton Brown J. Greenwood, T. Hai Phan, Y. Fujita, Z. Li, O. Ivasenko, W. Vanderlinden, H. Van Gorp, W. Frederickx, G. Lu, K. Tahara, Y. Tobe, H. Uji-i, S. Mertens and S. De Feyter

Kristin Brunner C. Methfessel, T. Torres, A. Hirsch, D. M. Guldi

Pawel Bugajny Ludmiła Szulakowska, Błażej Jaworowski, Paweł Potasz, Arkadiusz Wójs

Andrei Bylinkin D. Svintsov, V. Ryzhii, T. Otsuji

Qiran Cai Aijun Du, Bruce C. C. Cowie, Dong Qian, Yuerui Li, Takashi Taniguchi, Shaoming Huang, Ying Chen, Rodney S. Ruoff and Luhua Li

authors

country

topic

poster title

Gaetano Calogero N. J. van der Heijden, D. Smith, R.S. Koster, M.A. van Huis, I. Swart

Denmark

Theory and Simulation

The influence of the substrate on chemical identification of dopant atoms in graphene with AFM

Italy

Theory and Simulation

Coherency and anharmonicity in flexural phonons of graphene: a simulation study

USA

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Enhanced Chemical Vapor Sensing with MoS2 Using 1T/2H Phase Contacts/Channel

Sweden

Theory and Simulation

Chemical functionalization of Boron Doped Graphene for novel composite materials: application to catalytic nitric oxide reduction

France

Growth, synthesis techniques and integration methods

Co-Ir alloying upon intercalation of Cobalt ultrathin films under Graphene

Italy

Theory and Simulation

Defects in epitaxial graphene on Ni(111): first-principles simulations

Italy

Theory and Simulation

Functional approach to energy-exchange, application to the spin boson model for weak and strong coupling

Italy

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Micro-Raman investigation of the coupling to the metal substrate for graphene monolayers deposited by CVD on Cu foil

Spain

Composites for Energy applications

Evaluating layer-by-layer structures of different graphene/metal and graphene/metal oxide as electrodes for supercapacitors

Spain

Theory and Simulation

The role of the Fermi level pinning in gate tunable graphene/semiconductor junctions: Barristor

Taiwan

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Bandgap tunability of CVD monolayer WSe2 flakes by atomic force microscopy

Taiwan

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Enhanced Responsivities of InAs/GaSb Type-II Superlattice Infrared Photodetectors with Graphene Transparent Electrodes

Vito Dario Camiola R Farchioni, G. Garberoglio, V. Tozzini

Paul Campbell Adam L. Friedman, F. Keith Perkins, James C. Culbertson, and Aubrey T. Hanbicki

Valentina Cantatore Itai Panas

Ilaria Carlomagno J. Drnec, A.M. Scaparro, S. Cicia, C. Meneghini ,S. Vlaic, R. Felici

Virginia Carnevali Gianluca Prandini, Maria Peressi

Matteo Carrega Paolo Solinas, Alessandro Braggio, Maura Sassetti, and Ulrich Weiss

Enzo Cazzanelli I. B. Martins, R. E. P. de Oliveira, L. A. M. Saito and E. A. Thoroh de Souza

Stefanos Chaitoglou R. Amade, E. Bertran

Ferney A. Chaves R. David JimĂŠnez

Chang-Hsiao Chen Lain-Jong Li

Hsuan-An Chen Hsuan-You Chen and Shih-Yen Lin

authors

country

Kuan-Chao Chen Chong-Rong Wu, Xiang-Rui Chang, Si-Chen Lee and Shih-Yen Lin

topic

poster title

Taiwan

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Enhanced Field-Effect Mobility of MoS2 Transistors Prepared by Chemical Vapor Deposition with Low-Power Oxygen Plasma Treatment

Germany

Growth, synthesis techniques and integration methods

Precision synthesis of graphene nanoribbons by ambient-pressure chemical vapour deposition

Italy

Health and Medical Applications

Impact of graphene - related materials on primary glial cells

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Foldable Circuits and Organic Electronic Devices based on Solutionprocessed Graphene Composites and Inkjet Printing

Taiwan

Photonics and Plasmonics

Quantitative real-time and tunable band gap of deoxidization of graphene oxide using electrochemical surface plasmon resonance technology

UK

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Field Emission Applications of Graphene

Spain

Theory and Simulation

Optical versus quantum trajectories in the 2D Dirac equation: Targeting highfrequency performance and noise in graphene transistors

Chile

Quantum transport, magnetism and spintronics

Thermoelectric coefficients and quantum interference effects in trilayer silicene flakes

Romania

Health and Medical Applications

Influence of carboxyl graphene on the physical, chemical and biological performances of polysulfone porous films

Portugal

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Aqueous suspensions of few-layer graphene for composite thin films

Serbia

Theory and Simulation

Electron-phonon interaction anomalies in graphene and other layers

UK

Theory and Simulation

Fast relaxation of photo-excited carriers in 2D transition metal dichalcogenides

Zongping Chen Bilu Liu, Chongwu Zhou, Andrea Candini, Marco Affronte, Valentina De Renzi, Akimitsu Narita, Xinliang Feng and Klaus Müllen

Martina Chiacchiaretta Mattia Bramini, Silvio Sacchetti, Fabrizia Cesca and Fabio Benfenati

Byung Doo Chin Sung Min Jo, Dai Geon Yoon and Namsung Cho

Nan-Fu Chiu Cheng-Du Yang

Matthew Cole C. Li, C. M. Collins, R. J. Parmee, T. Hallam, W. Lei, S. Ding, B. P. Wang, G. Duesberg, & W. I. Milne

Enrique Colomés D. Marian, Z. Zhan and X. Oriols

Natalia Cortés L. Rosales, M. Pacheco, P. A. Orellana and Leonor Chico

Livia Elena Crica Mariana Ionita, Eugenia Vasile, Sorina Dinescu, Madalina A. Pandele, Marieta Costache, Håvard J. Haugen, Horia Iovu

Eunice Cunha Fernando Duarte, M. Fernanda Proença, M. Conceição Paiva

Milan Damnjanovic Mark Danovich Igor L. Aleiner, Neil D. Drummond, Vladimir I. Fal’ko

authors

country

topic

poster title

Lakshya Daukiya C. Mattioli, D. Aubel, S. Hajjjar-Garreau, F. Vonau, E. Denys, G. Reiter, J. Fransson, E. Perrin, M-L. Bocquet, C. Bena, A. Gourdon, and L. Simon

Elena del Corro Kentaro Sato, Miriam Peña-Álvarez, Ángel Morales-García, Milan Bousa, Martin Kalbac, Otakar Frank

France

Chemistry of 2D materials

Covalent functionalization by cycloaddition reactions of pristine, defect-free graphene

Czech Republic

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

The role of interlayer distance in the electronic properties of twisted bilayed graphene

Greece

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

A technology for graphene based millimeter wave integrated circuits

France

Theory and Simulation

Structural and electronic properties in the graphene/MoS2 heterostructure

Italy

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Binder-free graphene film via solvent exchange process as anode in Li-ion battery

Belgium

Quantum transport, magnetism and spintronics

Dirac electrons in constant magnetic fields: a tight-binding description of Landau levels and Hofstadter butterflies

Sweden

Theory and Simulation

Density functional theory calculations of graphene-based humidity and carbon dioxide sensors: effect of silica and sapphire substrates

Germany

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Millimetre-wave, Graphene-based power detector

France

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Graphene via electrochemical exfoliation: towards application in electronics

Finland

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Usage of printed graphene antennas in UHF RFID transponders

George Deligeorgis A.Ziaei, V. Prudkovskiy, F. Iacovella, S. Xavier, R. Yakimova, M. Modreanu and G. Konstantinidis

Daniela Di Felice César González and Yannick J. Dappe

Duc Anh Dinh Haiyan Sun, Antonio Esau Del Rio Castillo, Simone Monaco, Andrea Capasso, Alberto Ansaldo, Mirko Prato, Vittorio Pellegrini, Bruno Scrosati, Liberato Manna and Francesco Bonaccorso

Simon Dubois A. R. Botello-Mendez, J.-C. Charlier

Karim Elgammal Håkan W. Hugosson, Anderson D. Smith, Mikael Råsander, Lars Bergqvist, Anna Delin

Mohamed Elsayed Ahmed Hamed, Abhay Sagade, Zhenxing Wang, Daniel Neumaier, Renato Negra

Matilde Eredia Simone Bertolazzi, Artur Ciesielski and Paolo Samorì

Vladimir Ermolov Kaarle Jaakkola, Henrik Sandberg, Kaisa Kiri

authors Shi-Yuan Fan

country

topic

Taiwan

Chemistry of 2D materials

Carboxyl-modified graphene oxide be used in early detection of potentially pancreatic cancer

Italy

Theory and Simulation

Modelling doped Graphene for the Electrocatalysis of the Oxygen Reduction Reaction (ORR)

Russia

Composites for Energy applications

Polyaniline/Graphene Hybrid Material for the Electrochemical Supercapacitors

Spain

Theory and Simulation

A Drift-Diffusion Graphene Field Effect Transistor model to study scaling effects on High Frequency performance

France

Growth, synthesis techniques and integration methods

Toward new plasma procedure for efficient cleaning of high quality CVD graphene transferred onto SiO2/Si substrate

Italy

Composites for Energy applications

Graphene nanoplatelets for thermally conductive polymer nanocomposites via melt reactive extrusion

Ting-Li Lin, Nan-Fu Chiu

Gianluca Fazio Ferrighi L., Di Valentin C

Ekaterina Fedorovskaya Okotrub A.V., Bulusheva L.G.

Pedro C. Feijoo David Jiménez, Xavier Cartoixà

Djawha Ferrah O. Renault, J. Arias-Zapata, D. Marinov, H. Okuno, C. Berne, V. Bouchiat, G.Cunge

poster title

Alberto Fina S. Colonna, O. Monticelli, M. Tortello, R.S. Gonnelli, J. Gomez, M. Pavese, F. Giorgis, G. Saracco

Luděk Frank Eliška Mikmeková

Czech Republic

Teresa Galan Gabriele Navickaite, Stijn Goossens, Gerasimos Konstantatos, Frank Koppens

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Spain

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Doping control of graphene using Self-assembled monolayers

China

Chemistry of 2D materials

Robust Superhydrophobic Foam: A Graphdiyne-based Hierarchical Architecture for Oil/water Separation

Italy

Composites for Energy applications

Microwave-assisted synthesis of novel catalysts for the oxygen reduction reaction starting from graphene oxide and metallic precursors

Spain

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Engineering edge structure and electronic properties of graphene nanoislands by Au intercalation

Spain

Growth, synthesis techniques and integration methods

Effect of Temperature on the Growth of Single Crystalline Monolayer Graphene by Chemical Vapor Deposition (CVD)

Xin Gao Jingyuan Zhou, Ran Du, Zhongfan Liu, Jin Zhang

Nadia Garino Adriano Sacco, Micaela Castellino, Angelica Chiodoni, José A. Muñoz-Tabares, Marzia Quaglio

Michele Gastaldo Gustavo Ceballos, Aitor Mugarza

Zewdu M. Gebeyehu Jo Cuppens, Maria J. Esplandiu, Sergio O. Valenzuela

Ultralow energy SEM and STEM of graphene

authors

country

topic

Christa Genslein Hausler P., Kirchner E.-M., Rolka A., Baeumner A. J., Hirsch T.

Sumit Ghosh Aurelien Manchon

Germany

Photonics and Plasmonics

Nanohole Arrays Combined with Chemically reduced Graphene Oxide for Sensing

Saudi Arabia

Theory and Simulation

Wave Packet Dynamics in 2D materials

Italy

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Microwave performances dependence on geometry for Graphene Field Effect Transistors (GFETs)

Turkey

Composites for Energy applications

Improving hydrogen storage of graphene at room temperature with transition metal (Ti, Fe, Ni, Cu) functionalization

Australia

Health and Medical Applications

Multiphoton Fluorescence Spectroscopy in Conjunction with Activated Graphene Quantum Dots for Monitoring Tissue Regeneration and Drug Delivery

Colombia

Chemistry of 2D materials

Adsorption of toxic metal ions onto magnetic graphene oxide

UK

Growth, synthesis techniques and integration methods

The growth of porphyrin-based two-dimensional covalent organic frameworks (2D-COFs) via the Schiff base reaction

UK

Theory and Simulation

Nonlinear graphene plasmonics and photonics: manipulating light on a surface

Italy

Photonics and Plasmonics

Optically transparent microwave devices based on engineered graphene

Italy

Theory and Simulation

Application of super-expanded graphite for the treatment of soils contaminated with hydrocarbons

UK

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

InSe hybrid heterostructures and nanomechanical probing of the heterostructure interface

Marco Angelo Giambra L. Zeiss, A. Benfante, E. Calandra, S. Stivala, A. Busacca,

Zahra Gohari Bajestani Alp Yürüm and Yuda Yürüm

Vincent Gomes Sara Ardekani, Alireza Dehghani

poster title

Ivan Gomez E. Mejía-Ospino, R. Cabanzo Hernández

Niall Goodeal Matthew Blunt, Ya Hu, Hugo Bronstein

Andrey Gorbach

Marco Grande G. V. Bianco, M. A. Vincenti, D. de Ceglia, P. Capezzuto, V. Petruzzelli, M. Scalora, G. Bruno, A. D'Orazio

Michele Greco Salvatore Masi, L. Colangelo, Salvatore Lofiego, Stefania Calace, Domenico Molfese, Giuseppina Mazzone, Raffella Pascale, Donatella Caniani

Jake Greener R. Beardsley, G. W Mudd, N. Balakrishnan, S. Sandeep, Z.R. Kudrynskyi, A.V. Akimov, A. J. Kent, O. Makarovsky, Z.D. Kovalyuk, P.H. Beton, L. Eaves, A. Patanè

authors Roberto Guarino N. M. Pugno

Karina A. Guerrero-Becerra Andrea Tomadin, Marco Polini

country

Damien Hanlon Claudia Backes, Andrew Harvey, Jonathan Coleman

Ian Hayward Tim Batten

Theory and Simulation

Numerical simulation of the thermal performances of graphene-based lubricants

Italy

Quantum transport, magnetism and spintronics

Resonant tunneling and the quasiparticle lifetime in graphene/ boron nitride / graphene heterostructures

Italy

Growth, synthesis techniques and integration methods

Exploiting molecule-surface interaction to exfoliate few layers graphene in liquid

Ireland

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Stability Characterisation of Liquid-Exfoliated Black Phosphorus nanosheets

UK

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Fast Raman imaging of graphene grown on copper

UK

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Thermoacoustic generation in graphene field-effect transistors

Spain

Photonics and Plasmonics

Can graphene photodetectors break the quantum efficiency limit?

Norway

Growth, synthesis techniques and integration methods

Graphene-Si(111) thin film heterostructure by aluminum-induced crystallization

Korea

Growth, synthesis techniques and integration methods

Graphene Nanoplatelets derived from the Spheroidal Graphite

Taiwan

Composites for Energy applications

The Vertical Graphene Sheets as the Electrodes of Supercapacitor

Colombia

Chemistry of 2D materials

Efficient fluorescence quenching in electrochemically exfoliated graphene decorated with gold nanoparticles

Romania

Health and Medical Applications

Graphene Oxide Reinforced Gelatin–Poly(Vinyl Alcohol) Biomaterials as Scaffolds for Bone Tissue Engineering

Sweden

Theory and Simulation

Microscopic view on graphene-based photodetectors

Mark Heath D. W. Horsell

poster title

Italy

Niloofar Haghighian A. Penco, D. Convertino, A. Rossi, C. Coletti, F. Bisio, O. Cavalleri and M. Canepa

topic

Niels Hesp Klaas-Jan Tielrooij, Mark Lundeberg, Mathieu Massicotte, Frank Koppens

Ida Marie Høiaas Dong-Chul Kim and Helge Weman

Ikpyo Hong Eun Jung Lee, Jung-Chul An

Kun-Ping Huang Yu-Wen Chi

Mikel Fernando Hurtado Morales M. Ortiz, C. Acuña, H.C. Nerl, V. Nicolosi, Y. Hernandez

Mariana Ionita L. E. Crica, H. Tiainen, H. J. Haugen, E. Vasile, S. Dinescu, M. Costache, H. Iovu

Roland Jago Florian Wendler and Ermin Malic

authors

country

topic

poster title

Sihem Jaziri Emna Bensalem and Imen Ben Amara

Sihem Jaziri A. Daboussi , L. Mandhour

Khatuna Kakhiani Tommaso Cavallucci, Valentina Tozzini

Tunisia

Theory and Simulation

Exciton and trion features in MoS2/WS2 heterobilayer: Theoretical study

Tunisia

Theory and Simulation

Unusual zero-energy tunneling properties in shifted bilayer graphene

Italy

Theory and Simulation

Curvature-dependent chemisorption onto graphene for storage applications: a Density Functional Theory study

Spain

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Pyro-resistive infrared detector using graphene on LiNbO3

Czech Republic

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Tuning topography of graphene using monodisperse nanoobjects

Japan

Growth, synthesis techniques and integration methods

Reduced graphene oxide films produced from graphene oxide under an oscillating electric field around y-axis on x-z plane

India

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Improved Infrared Photodetection by Reduced Graphene Oxide

Norway

Growth, synthesis techniques and integration methods

Investigation of graphene growth on platinium by chemical vapor deposition

Korea

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Near Bandgap Ultrafast Carrier Dynamics of MoS2 Studied by Time-Resolved Second Harmonic Generation Microscopy

Korea

Health and Medical Applications

Human induced pluripotent stem cell on DAS nanocrystalline graphene for feeder-free culture system

USA

Growth, synthesis techniques and integration methods

Low-k organic dielectric engineering for graphene field effect transistors (GFETs)

Kavitha Kalavoor D. Janner,S. Nanot, R. Parret, F. Koppens, V. Pruneri

Jana Kalbacova Vejpravova Barbara Pacakova, Alice Mantlikova, Timotheus Verhagen, Vaclav Vales, Otakar Frank and Martin Kalbac

Fumito Kemuriyama S.Yamauchi, M.Takayama, T.Komiyama, Y.Chonan, H.Yamaguchi and T.Aoyama

Mustaque Ali Khan K.K.Nanda, S.B.Krupanidhi

Dong Chul Kim Jungtae Nam, Hoyeol Yun, Seungjin Nam, Jun Yeon Hwang, SangWook Lee, Helge Weman and Keun Soo Kim

Hyunmin Kim Houk Jang, Kyoung-Il Joo, Soon Moon Jeong, Jong-Hyun Ahn

Jeong Beom Kim Donggyu Nam, Hyunah Lee, Soon-Yong Kwon, Holm Zaehres, Hans R. Schoeler

Jiyoung Kim Lanxia Cheng, G. Mordi, Young Gon Lee

authors

country

Jung Ho Kim Seok Joon Yun, Jiong Zhao and Young Hee Lee

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Facile Synthesis of SnS-SnS2 Heterostructure p-n Diode

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Enhancement of electrical property of graphene by atomic layer deposition of Ru

Korea

Composites for Energy applications

One Pot Synthesis of Graphene-based Nanocomposites for Electrochemical Energy Storage Devices

Korea

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Raman fingerprints for thickness and crystallographic orientation of WTe 2

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Synthesis and Characterization of Composites using Hybrid Fillers of SiC Microparticle and SiC Nanoparticle Grafted Graphene Oxide

Korea

Growth, synthesis techniques and integration methods

Autonomous Graphene Vessel for Collecting Liquid Body of Spilled Oil

Germany

Chemistry of 2D materials

Studies of Graphene as Electrode Material for Sensor Applications

Germany

Health and Medical Applications

From rigid to flexible: graphene-based extracellular sensors

Sweden

Composites for Energy applications

Hydrogen storage in high surface area graphene scaffolds

Germany

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Electrical Characterization of Large Area Graphene Layers

Germany

Growth, synthesis techniques and integration methods

Floating transfer optimization of large-area chemical vapor deposition graphene on AlN as advanced electrodes for bulk acoustic wave devices

Kwang Bum Kim Hyun-Kyung Kim, Hee Chang Youn, Seok Woo Lee

Minjung Kim Jung Hwa Kim, Jae-Ung Lee, Zonghoon Lee and Hyeonsik Cheong

Sung-Ryong Kim MinhCanh Vu, Ye-Seul Song, Hee-Jin Lee, Jung-Yong Kim, Young-Han Bae, Min-Ji Yu

Taewoo Kim Jeong Seok Lee and Yong Hyup Kim

poster title

Korea

Ki-Ju kim Minsu Kim, Seoung-Joon Lee, Seong-Yong Cho, Hyun-Mi Kim, Soo-Hyun Kim and Ki-Bum Kim

topic

Eva-Maria Kirchner Baeumner A. J., Hirsch T.

Dmitry Kireev Qiu Tianyu, Dario Sarik, Silke Seyock, Tianru Wu, Vanessa Maybeck, Martin Lottner, Benno M. Blaschke, Jose Garrido, Xiaoming Xie, Bernhard Wolfrum, Andreas Offenhaeusser

Alexey Klechikov Guillaume Mercier, Alexandr Talyzin

Marcus Klein Martin Busch

Marius Knapp Katarzyna Holc, Vadim Lebedev, Oliver Ambacher, RenĂŠ Hoffmann

authors Martin Kon么pka

Sangkyun Koo Hooin Lee

Pekka Koskinen Topi Korhonen

country

Melanie Kucki Liliane Diener, Harald F. Krug, Peter Wick

poster title

Slovakia

Theory and Simulation

Graphene nanoribbons with electrodes attached at their corners

Korea

Theory and Simulation

Microstructure of particulate aggregates in colloidal suspension of carbon nano-particles

Finland

Theory and Simulation

Limits of stability in supported graphene nanoribbons subject to bending

Italy

Quantum transport, magnetism and spintronics

Electrical behavior of reduced graphene oxide thin films. Interplay of lateral size and chemical composition of single sheets

Switzerland

Health and Medical Applications

One but not the same: Uptake of graphene oxide by Caco-2 cells is dependent on cell morphology and topography

UK

Quantum transport, magnetism and spintronics

Magnetic and semiconducting properties in van der Waals InSe layered crystals incorporating transition metals

Taiwan

Health and Medical Applications

High sensitivity surface plasmon resonance bio-chip detect female cancer Indicator protein

Croatia (Hrvatska)

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Dynamical conductivity of graphene: the memory function approach

Poland

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Optical control of charge carrier density in monolayer MoS2 and WS2

UK

Growth, synthesis techniques and integration methods

Carbon Nitride Thin Film Materials: A new method for deposition of large area thin films of crystalline carbon nitride onto any substrate at room temperature

Italy

Composites for Energy applications

Graphene-polycarbonate composites: tailoring electrical and mechanical properties

Russia

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Gas- and bio-sensors based of graphene, produced by thermal destruction of SiC substrates

Alessandro Kovtun A. Vianelli, A. Liscio, M. Affronte and V. Palermo

topic

Zakhar Kudrynskyi M.A. Bhuiyan, F. Moro, O. Makarovsky, Z.D. Kovalyuk, L. Eaves, P.H. Beton, M.W. Fay, M. Matsuura and A. Patan猫.

Chia Tzu Kuo Nan-Fu Chiu

Ivan Kupcic Joanna Kutrowska Joanna Jadczak, Ewelina Zdanowicz, Piotr Sitarek, Ying-Sheng Huang, Leszek Bryja

Satyam Ladva William Travis, Tim Nunney, Richard White, Robert Palgrave

Emanuele Lago Peter S. Toth, Antonio E. Del Rio, Vittorio Pellegrini and Francesco Bonaccorso

Alexander Lebedev S. P. Lebede, S. N. Novikov, Yu. N. Makarov, V. B. Klimovich

authors Jeong Seok Lee Taewoo Kim, Junho Lee and Yong Hyup Kim

country

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

High Performance CNT Point Emitter with Electrical and Thermal Interfacial Graphene Layer

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

DNA-Gated Graphene Nanopore FETs

Korea

Photonics and Plasmonics

Uniaxial crumpled graphene structure as a spacer for improving plasmonic coupling

Korea

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Scan in arbitrary direction using Probe-rotating Atomic Force Microscopy

Republic of Korea

Composites for Energy applications

Nitrogen-doped Graphene for Supercapacitor Application with Highqualified Graphene

France

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

High frequency photodetection and optoelectronic mixing in CVD graphene

Australia

Chemistry of 2D materials

Functional Boron Nitride Nanomaterials

France

Chemistry of 2D materials

Confinement of Graphene Oxide Layers

France

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Bimodal HD-KFM and Resiscope Atomic Force Microcopy characterization of bidimensional materials and solar cells

Belgium

Theory and Simulation

Electronic and transport properties of two-dimensional conjugated polymer networks

Finland

Photonics and Plasmonics

Linearly polarized ultrafast pulse generation based on black phosphorus

Australia

Chemistry of 2D materials

Properties and Applications of “White Graphene”

Khang June Lee Byung Chul Jang, Hamin Park, Dae Yool Jung, Woonggi Hong, Tae Keun Kim, and Sung-Yool Choi

Sang Heon Lee Sang Hun Lee

Seung Yong Lee Min Wook Chung, Gun Soo Kim, Seong Ihl Woo

Pierre Legagneux A Montanaro, S Mzali, J-P Mazellier, O Bezencenet, C Larat, S Molin, L Morvan, D Dolfi1, B Dlubak, P Seneor, M-B Martin, S Hofmann, J Robertson, A Centeno and A Zurutuza

poster title

Korea

Jooho Lee Yongsung Kim, Min-Hyun Lee, Kunsun Eom, ChangSeung Lee

topic

Weiwe Lei Vadym Mochalin, Dan Liu, Si Qin, Yury Gogotsi and Ying Chen

Rafael Leite Rubim K. Bougis, S. Von-Pine, L. Navailles and F. Nallet

Emmanuel Lepleux Louis Pacheco, Nicolas F.Martinez

Aurélien Lherbier Jean-Joseph Adjizian, Simon M.-M. Dubois, Andrés Rafael Botello-Méndez and JeanChristophe Charlier

Diao Li Henri Jussila, Lasse Karvonen, Guojun Ye, Harri Lipsanen, Xianhui Chen, Zhipei Sun

Luhua Li

authors Jian Xiang Lian Y. Olivier and D. Beljonne

country

Dan Liu Weiwei Lei, Li He, Si Qin, Ying Chen

poster title

Belgium

Quantum transport, magnetism and spintronics

Modeling charge transport in the stripped graphene surface delineated by sp³ defects

Thailand

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Highly Sensitive and Selective Room Temperature NO2 Sensor Based on Ohmic Metal-Semiconductor Interfaces of Electrolytically Exfoliated Graphene/Flame-Made SnO2 Composite Films

Australia

Growth, synthesis techniques and integration methods

Large-scale synthesis of boron nitride based hybrid nanosheets for water cleaning

China

Theory and Simulation

Point defects in epitaxial silicene on Ag(111) surface

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

MoS2 lateral tunnel diode formed by chemical doping

USA

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Ultra-High Raman Enhancement on monolayer MoS2

Switzerland

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Alkali Metal Adsorption on Freestanding Graphene Observed by Means of LEEPS Microscopy

France

Chemistry of 2D materials

Graphene-coated oxides studied as support for mono- and bimetallic cobalt catalysts

Germany

Growth, synthesis techniques and integration methods

Ultra-fast synthesis of Graphene on poly-crystalline metal foils

Poland

Quantum transport, magnetism and spintronics

Monolayer and bilayer graphene in the presence of a strong magnetic field: FQHE

Portugal

Health and Medical Applications

Study of the functionalization of graphene surfaces for biosensing applications

Italy

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Thermal annealing of chemical vapor deposited graphene studied with spectroscopic ellipsometry

China

Chemistry of 2D materials

One-Dimensional Nanomaterials for Energy Storage

Chaikarn Liewhiran Nantikan Tammanoon, Anurat Wisitsoraat, Chakrit Sriprachuabwong, Ditsayut Phokharatkul, Adisorn Tuantranont, Sukon Phanichphant

topic

Hongsheng Liu Haifeng Feng, Yi Du, Jian Chen, Kehui Wu, Jijun Zhao

Xiaochi Liu Jungjin Ryu, Minsup Choi, Deshun Qu and Won Jong Yoo

John R. Lombardi Cyril Muehlethaler, Christopher R. Considine, Vinod Menon, Wei-Chen Lin, Yi-Hsien Lee

Marianna Lorenzo J. Vergés, C. Escher, J.-N.Longchamp and H.W. Fink

Wen Luo Spyridon Zaferatos

Helge Lux P. Siemroth, S. Schrader

Patrycja Łydżba Janusz Jacak

George Machado Jr. R. Campos, J. Borme, P. Alpuim

Michele Magnozzi Vaidotas Miseikis, Camilla Coletti, Francesco Bisio, Maurizio Canepa

Liqiang Mai

authors

country

topic

Rishi Maiti Pratyusha Das, Camilla Baratto, Giorgio Sberveglieri, Bhaktha B N Shivakiran and Samit K Ray

Italy

Photonics and Plasmonics

Few-layered graphene oxide embedded 1DPhC microcavity for amplified spontaneous emission source

Iran

Growth, synthesis techniques and integration methods

Facile synthesis of palladium nanoparticles decorated nitrogen doped graphene and their catalytic study for acetylene hydrogenation in excess ethylene

Italy

Composites for Energy applications

Photovoltaic Applications of Colloidal Quantum Dot-Reduced Graphene Oxide Hybrid Materials

Spain

Theory and Simulation

Solitary Wave Interactions in Graphene Superlattices

Italy

Chemistry of 2D materials

Contamination-free suspended graphene structures by a Ti-based transfer method

South Africa

Chemistry of 2D materials

Synthesis of h-BN nanodots embedded-graphene hybrid films by atmospheric pressure CVD

Russia

Health and Medical Applications

Safety Assessment in Using PolyGraphene During Pre-Clinical Tests of the Enterosorption

Germany

Theory and Simulation

First-principles study of graphene nanoribbons deposited on the topological insulator Sb2Te3

Russia

Theory and Simulation

An exact-diagonalization-based scheme for solving the extended DMFT equations

Colombia

Growth, synthesis techniques and integration methods

Synthesis and characterization of nanocomposite of RGO@Ag@Au for Photocatalytic degradation of Rhodamine B

Brazil

Quantum transport, magnetism and spintronics

Magnetoresistance and spin-to-charge-current conversion in yttrium iron garnet-graphene hybrid structure

Firozeh Mansourkhani Alireza Badiei, Ali Morad Rashidi, Saeid KHajehmandali

Beatriz Martín-García Davide Spirito, Roman Krahne and Iwan Moreels

poster title

Francisca Martin-Vergara Rus, F. and Villatoro, F.R.

Alessia Matruglio Silvia Nappini, Denys Naumenko, Elena Magnano, Federica Bondino, Marco Lazzarino, Simone Dal Zilio

Boitumelo Matsoso Bridget Mutuma, Kamala Ranganathan, Tsenolo Lerotholi, Glenn Jones and Neil J. Coville

Evgeny Mazin Alexander Botin, Vladimir Buravtsev, Tamara Popova

Riccardo Mazzarello Farideh Hajiheidari, Wei Zhang, Yan Li

Darya Medvedeva V.V. Mazurenko, S.N. Iskakov, A.I. Lichtenstein

Enrique Mejía-Ospino Sol Esmeralda Castellanos, Rafael Cabanzo

Joaquim B. S. Mendes Obed Alves Santos, Leonel M. Meireles, Rodrigo G. Lacerda, Luis H. Vilela-Leão, Fernando L. A. Machado, Roberto L. Rodríguez-Suárez, Antonio Azevedo, and Sergio M. Rezende

authors Michele Merano

country

poster title

Italy

Photonics and Plasmonics

Fresnel coefficients of a two-dimensional atomic crystal

Germany

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Electrical contacts in graphene devices - 2D vs. 1D contact architecture

Italy

Growth, synthesis techniques and integration methods

Highly efficient growth conditions for monolayer graphene films by ethanol chemical vapor deposition: observation of the initial growth stages

Germany

Growth, synthesis techniques and integration methods

Current annealing recovery from electron beam induced damages in suspended graphene

Iran

Chemistry of 2D materials

Graphene-based NO2 gas sensor: Synthesis and Characterisation

Italy

Composites for Energy applications

Thermal and electrical properties of graphene-based thermoset composites: a study on the role of graphene nano-platelets morphology

Italy

Photonics and Plasmonics

Plasmon propagation enhancement in graphene waveguides via antenna design and nanopatterning

Italy

Growth, synthesis techniques and integration methods

Rapid and catalyst-free van der Waals epitaxy of graphene on hBN

Italy

Theory and Simulation

Growth of nanoparticles on supported graphene: insights from ab-initio calculations

Malaysia

Growth, synthesis techniques and integration methods

Tuneable layers of Three Dimensional Graphene Structure Grown using Chemical Vapour Deposition

Germany

Theory and Simulation

Multiscale modeling of heat transfer in graphene/h-BN polycrystalline heterostructures

Wolfgang Mertin Carlos Alvarado Chavarin, Abhay A. Sagade, Mehrdad Shaygan, Daniel Neumaier, Gerd Bacher

topic

Giacomo Messina Angela Malara, Andrea Gnisci, Giuliana Faggio, Theodoros Dikonimos, Francesco Buonocore, Andrea Capasso, Nicola Lisi

Alessio Miranda Axel Lorke

Mona Mirmotallebi Vardan Galstyan, Andrea Ponzoni, Iskandar Kholmanov, Azam Iraji zad and Giorgio Sberveglieri

Nicola Mirotta Alessandro Kovtun, Emanuele Treossi, Tamara Blanco, Julio G贸mez, Alberto Fina and Vincenzo Palermo

Mario Miscuglio Davide Spirito, Roman Krahne

Neeraj Mishra Vaidotas Miseikis, Domenica Convertino, Mauro Gemmi, Vincenzo Piazza, Camilla Coletti

Fatema Mohamed Marco Pividori, Maria Peressi

Norani Muti Mohamed Mohamed Salleh Mohamed Saheed, Balbir Singh Mahinder Singh, Mohamed Shuaib Mohamed Saheed

Bohayra Mortazavi Raahul Palanivel Uma, Gianaurelio Cuniberti, Timon Rabczuk

authors

country

Nunzio Motta I. Di Bernardo, B. Gupta, P. Mondelli, A. Della Pia, M.G. Betti, F. Iacopi, C. Mariani

poster title

Italy

Growth, synthesis techniques and integration methods

Effect of substrate polishing on the growth of graphene on 3CSiC(111)/Si(111) by high temperature annealing

France

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Sharp structural characterization of G/h-BN heterostructures by HRTEM

Brazil

Theory and Simulation

Ab initio calculation of optical absorption in twisted multilayer graphene

Israel

Growth, synthesis techniques and integration methods

Graphene Nanoribbon - Polymer Composites: The Critical Role of Edge Functionalization

Italy

Composites for Energy applications

Exfoliated MoS2 flakes as hole transport layer in perovskite-based photovoltaics

Italy

Composites for Energy applications

Enhanced hydrogen release properties of light metal-borohydrides mixed with Reduced Graphene Oxide

Belgium

Theory and Simulation

Transport properties through a single grain boundary in graphene systems: strain effects versus lattice symmetry

Australia

Growth, synthesis techniques and integration methods

FlexeGRAPH: Graphene and 2D Materials Production at The Australian National University

Italy

Composites for Energy applications

Graphene composite electrospun fibres: mechanical and morphological characterization

UK

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Carbon based resistive random access memories with graphene electrodes

UK

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Graphene as protective coating for ultra-high storage density hard disks

Ouafi Mouhoub C.Ricolleau, G. Wang , A. Andrieux, F. Fossard, N. Dorval, P. Lavenus, H. Amara, A. Loiseau, D. Alloyeau

topic

Marcus Moutinho A. Viana; E. H. M. Ferreira; C. M. Almeida; P. Venezuela; R. B. Capaz; A. Jorio; L. G. Canรงado; C. A. Achete; M. M. Lacerda

Roey Nadiv Michael Shtein, Matat Buzaglo, Sivan PeretzDamari, Anton Kovalchuk, Tuo Wang, James M. Tour and Oren Regev

Leyla Najafi A. Capasso, F. Matteocci, A.E. Del Rio Castillo, V. Pellegrini, A. Di Carlo and F. Bonaccorso

Angeloclaudio Nale Flavio Pendolino, Amedeo Maddalena and Paolo Colombo

Viet-Hung Nguyen Philippe Dollfus and Jean-Christophe Charlier

Shannon M. Notley

David Novel Alessandro Pegoretti, Nicola Maria Pugno

Anna Katharina Ott C. Dou, U. Sassi, I. Goykhman, A. C. Ferrari

Anna Katharina Ott N. Dwivedi, R. J. Yeo, C. Dou, U. Sassi, D. De Fazio, C. S. Bhatia and A. C. Ferrari

authors

country

topic

poster title

Gioele Pagot Federico Bertasi, Giuseppe Pace, Keti Vezzù, Enrico Negro, Antoine Bach Delpeuch, Graeme Nawn and Vito Di Noto

Italy

Composites for Energy applications

Hydrothermal Synthesis of Vanadium Sulfate supported on Graphene Oxide as Novel Cathode for Magnesium Ion Batteries

Greece

Chemistry of 2D materials

Doping-induced rhombohedral to Bernal structural transformation in trilayer graphene

Korea

Chemistry of 2D materials

Surface passivation effect on the bias-stress-induced instability of CVDgrown molybdenum disulfide transistor

Korea

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Large-area, Highly Sensitive MoS2/Graphene Tactile Sensors and Their Performance for Electronic Skin Applications

Greece

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Polymer/ graphene "pastry" for flexible touch screens

Spain

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Large-signal model of graphene field-effect transistors

Poland

Growth, synthesis techniques and integration methods

Large-area high-quality graphene on Ge(001)/Si(001) substrates

Spain

Theory and Simulation

Electronic Properties of Corrugated Bilayer Graphene

Italy

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)q

Nanotribology of inkjet printed graphene flakes

Italy

Chemistry of 2D materials

Self-Assembly of Carbon Nanohorn Oxide

France

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Electronic interaction between organic molecules and nitrogen-doped graphene

Finland

Growth, synthesis techniques and integration methods

High Concentration Surfactant-Polymer Stabilized Few-layer Graphene Sheets

Konstantinos Papagelis J. Parthenios, C. Galiotis, N. Delikoukos, D. Tasis

Hamin Park Tae Keun Kim, Seung-Bum Seo, Gi Woong Shim and Sung-Yool Choi

Yong Ju Park Minhoon Park, Min-Seok Kim, Jong-Hyun Ahn

John Parthenios G.Anagnostopoulos, G. Paterakis, C. Galiotis and K. Papagelis

Francisco Pasadas David Jiménez

Iwona Pasternak P. Dabrowski, P. Ciepielewski, Z. Klusek, J. M. Baranowski, W. Strupinski

Marta Pelc W. Jaskólski, A. Ayuela and L. Chico

Luca Pellegrino R. Buzio, A. Gerbi, S. Uttiya, C. Bernini, A.E. Del Rio Castillo, V. Pellegrini, A.S. Siri and F. Bonaccorso

Flavio Pendolino Colombo Paolo

Van Dong Pham Vincent Repaint, Cyril Chacon, Amandine Bellec, Yann Girard, Jerome Lagoute, Sylvie Rousset

Josphat Phiri Patrick Gane, Thad Maloney

authors Ilya Piterskikh V.Mazurenko

country

topic

poster title

Russia

Theory and Simulation

First-principle study of functionalized graphene

Italy

Growth, synthesis techniques and integration methods

Improving the cleanliness of graphene grown on copper by chemical vapor deposition for biosensing applications

Belgium

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Transition Metal Contact Studies on Single- and Multilayer Graphene Ribbons

Poland

Photonics and Plasmonics

Energy transfer between plasmon-enhanced up-converting α-NaYF4:Er3+/Yb3+ nanocrystals to graphene

China

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Controllable Synthesis of Graphene Using Novel Aromatic 1,3,5Triethynylbenzene Molecules on Rh(111)

Australia

Growth, synthesis techniques and integration methods

N-doped Mesoporous Molybdenum Disulfide Nanosheets: Synthesis and Application in Lithium Ion Batteries

China

Chemistry of 2D materials

Rapid Growth of Large Single-crystal Graphene by Cooperative Passivation Method towards High-quality Film

Italy

Composites for Energy applications

Graphene foams as new cathode and anode materials for microbial fuel cells

USA

Theory and Simulation

Berry's Phase and Giant Non-Reciprocity in Graphene Quantum Dots

Chile

Quantum transport, magnetism and spintronics

Silicene-based spin filter device: Impact of random vacancies

Germany

Chemistry of 2D materials

Transfer of Electrochemically Amino-functionalized Large Area Graphene

Poland

Quantum transport, magnetism and spintronics

Pseudodiffusive magnetotransport in bilayer graphene Corbino disks

Martina Pittori R. Brajpuriya, E. Leoni, A. Capasso, T. Dikonimos, F. Buonocore, R. Mazzaro, V. Morandi, R. Rizzoli, M.G. Santonicola, N. Lisi

Maria Politou Inge Asselberghs, Xiangyu Wu, Iuliana Radu, Cedric Huyghebaert, Zsolt Tokei, Stefan De Gendt, Marc Heyns

Aneta Prymaczek K. Ciszak, M. Nyk, S. Winters, I. Kamińska, D. Piątkowski, G. S. Duesberg, S. Maćkowski

Yue Qi Yanfeng Zhang, Zhongfan Liu

Si Qin Weiwei Lei, Dan Liu and Ying Chen

Huaying Ren Hailin Peng and Zhongfan Liu

Rita Rizzoli M. Christian, L. Ortolani, V. Palermo, V. Margaria, A. Sacco, N. Garino, A. Chiodoni, M. Quaglio, V. Morandi, C.F. Pirri

Joaquin Rodriguez-Nieva Mildred S. Dresselhaus, Leonid S. Levitov

Luis Rosales C. D. Nuñez, P. A. Orellana, F. DomínguezAdame, R. A. Römer

Felix Rösicke Marc A. Gluba, Guoguang Sun, Karsten Hinrichs, Jörg Rappich and Norbert H. Nickel

Grzegorz Rut Adam Rycerz

authors Marta Saiz-Bretín F. Domínguez-Adame and A. V. Malyshev

country

topic

Spain

Theory and Simulation

Thermoelectric properties of graphene nanorings

Spain

Composites for Energy applications

Boosting energy storage performance of commercial Fe3O4 Nanoparticles by facile anchoring on rGO Nanosheets

Italy

Composites for Energy applications

Electro-Spun Self-Standing CoOx/C/Graphene Mats as Binder-Free Anodes for Flexible Li-ion Batteries: Performances and Perspectives

UK

Photonics and Plasmonics

Cavity integrated silicon-graphene Schottky photodetectors

Italy

Growth, synthesis techniques and integration methods

CVD growth and characterization of Graphene on Ge(100) substrates

Germany

Composites for Energy applications

Graphene-Based Nanocomposites as Catalyst Support in High Temperature PEM Fuel Cells

India

Chemistry of 2D materials

Self-propagated combustion based exfoliation of graphite: A colossal step towards large-scale production of graphene and its application in water desalination

Denmark

Theory and Simulation

Valley filtering and splitting using nanobubbles in graphene

China

Growth, synthesis techniques and integration methods

Direct synthesis of few-layer graphene on NaCl crystals

Malaysia

Composites for Energy applications

Effect of TiO2 /graphene nanocomposite in multilayer photoanode on the performance of dye sensitized solar cell

Jaime Sanchez Afshin Pendashteh, Jesus Palma, Marc Anderson, Rebeca Marcilla

poster title

Saveria Santangelo Patrizia Frontera, Fabiola Pantò, Sara Stelitano, Yafei Fan, Nicola Pinna, Enza Fazio, Marcello Marelli, Fortunato Neri, Pierluigi Antonucci

Ugo Sassi M. Casalino, I. Goykman, A. Eiden, G. Coppola, S. Milana, E. Lidorikis, D. De Fazio, F. Tomarchio, M. Iodice, L. Sirleto and A. C. Ferrari

Andrea Maria Scaparro V. Miseikis, C. Coletti, A. Notargiacomo, M. Pea, M. De Seta, L. Di Gaspare

Dana Schonvogel Peter Wagner, Alexander Dyck, Carsten Agert and Michael Wark

Soujit Sen Gupta Ramesh Kumar Soni, Manonmani Mohandoss, Anirban Som, Shihabudheen M. Maliyekkal and T. Pradeep

Mikkel Settnes Stephen R. Power & Antti-Pekka Jauho

Liurong Shi Zhongfan Liu

Mohamed Shuaib Norani Muti Mohamed, Seyed Esmaeil Mahdavi Ardakani, Balbir Singh Mahinder Singh, Mohamed Saheed

authors

country

Peter Siffalovic M. Hodas, K. Vegso, M. Pelletta, Y. Halahovets, M. Jergel and E. Majkova

Stefano Signetti Simone Taioli and Nicola M. Pugno

topic

poster title

Slovakia

Growth, synthesis techniques and integration methods

Copper growth on graphene - in situ X-ray scattering study

Italy

Theory and Simulation

Impact properties and related scalings of single layer graphene, hexagonal boron nitride, and hybrid multilayer 2D nanoarmors

Slovakia

Health and Medical Applications

Confocal Raman spectroscopy study of intracellular localization of graphene oxide nanoplatform under development for targeted delivery to cancer cells

Italy

Composites for Energy applications

Storing Hydrogen in graphene based materials

Italy

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Light Detection with Nanocrystal Sensitized Graphene

USA

Growth, synthesis techniques and integration methods

Multi-Process Graphene-CNT-TMD R&D Platform

Thailand

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Electrolytically Exfoliated Graphene/Flame-spray-made Vanadium-doped SnO2 Composite Films for Nitric Oxide Sensing

Italy

Composites for Energy applications

Influence of graphene flakes morphology on the lithium ion storage capability

Russia

Photonics and Plasmonics

Plasmons in tunnel-coupled graphene layers: backward waves with gain

India

Health and Medical Applications

Computational and Impedimetric Studies on Sub-picomolar Ammonia Sensing Using Fluorographene

Italy

Composites for Energy applications

Sprayed mesoporous graphene doped TiO2 film as an electron transport layer for perovskite photovoltaic devices

Marianna Sohova Michal Bodík, Peter Šiffalovič, Matej Jergel, Tibor Hianik, Nikola Bugárová, Zdeno Špitálsky, Mária Omastová, Martina Labudová, Silvia Pastoreková, Eva Majková

Giorgio Speranza E. Setijadi, Bartali R., Laidani N., KF AgueyZinsou, Crema L.

Davide Spirito Stefan Kudera, Vaidotas Miseikis, Carlo Giansante, Camilla Coletti, Roman Krahne

Karlheinz Strobl

Jirasak Sukunta Anurat Wisitsoraat, Chakrit Sriprachuabwong, Ditsayut Phokharatkul, Adisorn Tuantranont, Sukon Phanichphant, Chaikarn Liewhiran

Haiyan Sun Alberto Varzi, Duc Anh Dinh, Rinaldo Raccichini, Antonio Esau Del Rio Castillo, Roberto Cingolani, Vittorio Pellegrini, Bruno Scrosati, Stefano Passerini and Francesco Bonaccorso

Dmitry Svintsov Zh. Devizorova, V. Ryzhii, T. Otsuji

Kiran Kumar Tadi Tharangattu N. Narayanan

Babak Taheri Antonio Agresti, Sara Pescetelli, Aldo Di Carlo

authors

country

topic

poster title

China

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Artificial Stacking for Large Twisted Bilayer Graphene Domain with Van Hove Singularity

Germany

Theory and Simulation

Electronic Structure of Stacking-Faults in Graphite

China

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Raman Enhancement on Anisotropic Two-dimensional Layered Materials

Iran

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Design of a Broad-band Tunable Absorber Using Geraphene-Metal Metasurfaces

Italy

Theory and Simulation

Morphing graphene at the nano-scale: from simulations to applications

Italy

Theory and Simulation

Novel Ba doped graphene reconstruction: a First-principles study

Italy

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Tribological influence due to topological disorder in graphene

Joanna Niedziółka-Jönsson, Sinéad Winters, Georg S. Duesberg, Sebastian Maćkowski, Izabela Kamińska

Poland

Photonics and Plasmonics

Graphene vs. reduced graphene oxide: fluorescence quenching in hybrid nanostructures

Cristina Varone

The Netherlands

Growth, synthesis techniques and integration methods

Nucleation and growth of graphene

Germany

Theory and Simulation

Interplay between nanometer-scale strain variations and externally applied strain in graphene

Germany

Quantum transport, magnetism and spintronics

Nonlocal resistance in plasma hydrogenated graphene

Germany

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Novel non-covalent electron donor-acceptor system based on a push-pull conjugate and exfoliated graphite

Zhenjun Tan Hailin Peng and Zhongfan Liu

Manfred Taut K.Koepernik and M.Richter

Lianming Tong Jingjing Lin, Na Zhang, Nannan Mao, Jin Zhang

Elahe Sadat Torabi Arya Fallahi and Alireza Yahaghi

Valentina Tozzini Tommaso Cavallucci, Khatuna Kakhiani, Vito Dario Camiola, Riccardo Farchioni, Yuya Murata, Stefan Heun, Vittorio Pellegrini

Cesare Tresca Nikolay Verbitskiy, Alex Fedorov, Luca Petaccia , Alex Gruneis and Gianni Profeta

Manoj Tripathi Awaja, S. Signetti, N.M. Pugno

Magdalena Twardowska

G.C.A.M. Janssen

Gerard Verbiest S. E. Huber, M. Andersen, C. Stampfer and K. Reuter

Tobias Völkl Thomas Ebnet, Philipp Nagler, Tobias Korn, Christian Schüller, Dieter Weiss, Jonathan Eroms

Michel Volland S. Decurtins and D. M. Guldi

authors

country

topic

Shih-Han Wang Liren Tsai, Yi-Han Yen, Chin-Ying Lin, Jing-Hui Wang and Ming-Der Ger

Taiwan

Health and Medical Applications

Iridium Oxide Nanoparticle Decorated Reduced Graphene Oxide for Reduction Sensing Hydrogen Peroxide

France

Devices for Electronic Applications (flexible displays, high frequency devices, sensors, etc.)

Small Gate Length Microwave Graphene Transistor on Kapton Substrate

Switzerland

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Visualization of unoccupied states in the electronic structure of freestanding graphene by means of low-energy electron point source microscopy

Poland

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Energy transfer depends on the number of graphene layers

Poland

Growth, synthesis techniques and integration methods

Substrate interaction in graphene on hexagonal boron nitride

Wei Wei E. Pallecchi, A. Centeno, B. Alonso, Z. Amaia, S. Borini, S. Haque, M. Belhaj, H. Happy

Flavio Wicki Jean-Nicolas Longchamp, Tatiana Latychevskaia, Conrad Escher & Hans-Werner Fink

Kamil Wiwatowski Magdalena Twardowska, Justyna Grzelak, Sebastian Maćkowski, Izabela Kamińska

Igor Wlasny P. Kazimierczak, J. Łysiak, R. Stepniewski, Z. Klusek , A. Wysmołek

Ying Wu Adelina Ilie and Simon Crampin

poster title

UK

Theory and Simulation

Self consistent charge and dipole density functional tight binding method and its application to carbon-based systems

Zhenyuan Xia Francesca Leonardi, Marco Gobbi,Yi Liu, Vittorio Bellani, Andrea Liscio, Alessandro Kovtun, Rongjin Li, Xinliang Feng, Emanuele Orgiu, Paolo Samorì, Emanuele Treossi, Vincenzo Palermo

Qin Xie Lei Liao, Zhongfan Liu

Italy

Chemistry of 2D materials

Covalent grafting of self-assembled aryl diazonium salt on graphene via electrochemical reduction

China

Chemistry of 2D materials

Fabrication of Chemical Graphene Nanoribbons via Edge-selective Covalent Modification

USA

Growth, synthesis techniques and integration methods

Synthesis of millimeter-size monolayer epitaxial graphene with uniform strain and record magnetotransport

China

Health and Medical Applications

The Difunctional Features of Grapheme Oxide in Amyloid Aggregation

The Netherlands

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Growth of Germanium on Highly Oriented Pyrolytic Graphite

Yanfei Yang Guangjun Cheng, Chiashain Chuang, ChiehWen Liu, Angela R. Hight Walker, Eric A. Lass, and Randolph E. Elmquist

Yanlian Yang Huan Huang, Qunxing Huang, Maryam Yousaf, Changliang Liu, Min Zhang, Chen Wang

Qirong Yao L. Zhang, W.J. Kwieciński, H.J.W. Zandvliet

authors Seok Joon Yun Young Hee Lee

Dawei Zhai Nancy Sandler

country

topic

Korea

Growth, synthesis techniques and integration methods

The Facile way for converting chalcogen in transition metal dichalcogenides

USA

Theory and Simulation

Dynamical energy gap engineering in graphene via oscillating out-of-plane deformations

Spain

Theory and Simulation

Improving the intrinsic cut-off frequency of graphene transistors without channel length scaling: going beyond the quasi-static approximation

Hong Kong SAR

Quantum transport, magnetism and spintronics

Two Dimensional Anderson Mobility Edge in Antidot Graphene

China

Composites for Energy applications

Enhanced photocatalytic Performance of TiO2 nano-rods and nano-crystals using graphene as a cocatalyst

China

Chemistry of 2D materials

Two-Dimensional MoS2/WS2 Heterostructure Synthesized from WO3-x/MoO3-x Core-Shelled Nanowires

China

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Monolayer MoS2 and MoS2/Graphene heterostructures synthesized on Au foils by chemical vapor deposition method

China

Health and Medical Applications

Biomass graphene nanosheets prepared based on group coordination assembly method using corn cobs cellulose and its application in HealfiberÂŽ

China

Growth, synthesis techniques and integration methods

Synthesis of Graphdiyne Nanowalls using Glaser-Hay Coupling Reaction

China

Spectroscopies (Optics, Raman, EELS) and microscopies (HRTEM, STM, AFM)

Periodic Quasiparticle Energy Band Tunability in Striped MoS2 Superstructures

Zhen Zhan E. ColomĂŠs, A. Benali and X.Oriols

Haijing Zhang Ping Sheng

Long Zhang Yanfeng Ma, Yongsheng Chen

Qi Zhang Liying Jiao

Yanfeng Zhang

Yingfu Zheng Tang Yilin, Zhang jinzhu, Liu Xiaomin

Jingyuan Zhou Ziqian Xie, Rong Liu, Xin Gao, Jin Zhang, Zhongfan Liu

Xiebo Zhou Jianpin Shi, Yanfeng Zhang, Zhongfan Liu

poster title