The product of the hole concentration and the conduction electron concentration turns out to be independent of the amount of any impurity doped. The concentration of conduction electrons in germanium is 6 × 10 19 per cubic meter. When some phosphorus impurity is doped into a germanium sample, the concentration of conduction electrons increases to 2 × 10 23 per cubic meter. Find the concentration of the holes in the doped germanium.

Question

Philoid · Accepted Answer

Given:

Initially,

Concentration of conduction electron

Concentration of holes

After doping,

Concentration of conduction electron

Concentration of holes

We know,

Product of concentration of conduction electron and that of holes remains constant,

∴

∴ number of holes after doping