Question

Distinguish between an intrinsic semiconductor and p-type semiconductor. Give reason, why a p-type semiconductor crystal is electrically neutral, although nh >> ne?

Answer 1

 Intrinsic semi-conductor is a pure semi-conducting material. No impurity atoms are present in it or added to it. A p-type semi-conductor is an extrinsic semi-conductor obtained by doping the impurity of trivalent atoms such as Al, B, In, etc. to an intrinsic semi-conductor. The charge of additional charge carriers present in a p-type semi-conductor are just equal and opposite to that of the ionised cores in the lattice. These additional charge carriers are balanced out by the ionised cores. Hence, a p-type semi-conductor is electrically neutral.