1.Explain the variation of carrier concentrations and Fermilevel position in a semiconductor with increase in doping. 2.The doping profile in a semiconductor is given by N D (x) = N (0) e –ax . If N D (x) >> n i , determine the built in field. Plot its energy band diagram. 3.Show that the maximum resistivity of a semiconductor at a given temperature with intrinsic carrier concentration n i is )pn()nq2( 1 imax (Pages : 3) P.T.O. Reg. No. : ..................................... .2 1 −