When Arsenic atoms are added to Germanium lattice, it becomes a/an

Options

A. Insulator
B. Superconductor
C. Intrinsic semiconductor
D. Extrinsic semiconductor

Answer

D

Explanation

When a pentavalent (donor) impurity, like arsenic, is added to germanium, it will form covalent bonds with the germanium atoms, leaving 1 electron relatively free in the crystal structure. Pure germanium may be converted into an N-type semiconductor by doping it with any donor impurity having 5 valence electrons in its outer shell. Semiconductors which are doped in this manner - either with Nor P-type impurities - are referred to as EXTRINSIC semiconductors.