Atomic Force Microscopy Pros and Cons
Atomic Force Microscopy is growing in demand around the world, but just like any other device, it has it's limitations. When deciding whether to analyze a sample using an AFM, you need to know the pros and cons of the device to ensure you use the right equipment for the project. Atomic force microscopy offers many great advantages when compared to scanning electron microscopes. AFM's provide the convenience of three dimensional profiles, rather than the two dimension provided by the scanning elecron microscope. In addition to this, when using an atomic force microscope, you don't have to do any special treatment to the sample, so no need to provide a metal coating, which can damage the sample. Unlike the scanning electron microscope that requires a vacuum environment to operate effectively, the atomic force microscope can work in ambient air and in liquid, making it ideal for studying living organisms. AFM's are also able to provide the highest resolution images. The images produced are significantly better quality than the scanning electron microscope, showing rue atomic resolution. When choosing the best imaging technique for your particular sample, you also need to know the disadvantages of the atomic force microscope. The biggest downside of these devices is their single scan image size. Scanning electron microscopes, for example are able to image an area in square millimeters with depth of field based on the order of millimeters. The AFM, on the other hand, only images a maximum height in ten to twenty micrometers with maximum scanning area being 150 x 150 micrometers. When it comes to scanning speed, the AFM falls short when compared to the scanning electron microscope. Scanning electron microscopes scan close to real time, but their quality isn't as high. The AFM takes a good few minutes to carry out a scan, but offers a higher quality image. The slow imaging speed has been known to result in a thermal drift, which makes it difficult on topographical projects, this has been eliminated using new methods, which have been introduced. It's not uncommon to have to use software filtering and enhancements on AFM images, due to the hystersis effect of piezoelectric materials and the cross in the x, y, z axles. This can result in topographical features being flattened. These problems have mostly been eliminated in the newer AFM products. The final disadvantage you need to be aware of is that atomic force microscopes are not good at measuring overhangs and steep walls. For this you need a specifically designed cantilever which can move up and down and side to side. When choosing between the different imaging methods, it's also important to focus on the suppliers and the quality of the product, ensuring you achieve accurate results. There are numerous AFM products on the market, supplied by a host of specialists. This is why you need to follow some important steps to ensure you make the right selection, spending your budget wisely.