Question

A semiconductor is doped with a donor impurity:

Answer 1

Hint: Donor impurity means Doping of semiconductors wherein we purposely introduce defects or impurities onto our semiconductor material. The doping material is called dopant. Doping material is typically of a concentration so low that the overall crystal quality of the semiconductor is not compromised.

Complete answer:
Depending on the dopant material, the semiconductor's charge carrier concentration may be changed either toward a more positive or more negative value.
Semiconductors are defined as those materials which have a conductivity between conductors (generally metals like iron) and nonconductors or insulators (such as most ceramics).
Semiconductors can be pure elements, such as silicon or germanium, or compounds such as gallium arsenide or cadmium selenide.
A semiconductor is when doped with a donor impurity will increase the concentration of electron and at the same time donor impurities will decrease the hole concentration by favouring recombination of the whole electron pair.
As we know, Donor impurities provide its excess electrons present in its outermost shell to the other atom of the crystal structure. While in case of acceptor impurity when added to a semiconductor then it accepts the charge from the neighbouring atom of the crystal structure.
Therefore, we conclude when the hole concentration is decreased and the electron concentration increases.

Note: Donor impurity is defined as dopant having 5 electrons in its valence shell when doped with a semiconductor like silicon, germanium, gallium arsenide etc. to increase its conductivity is known as a donor impurity. It holds the capacity to donate an extra (more) electron present in its valence shell to the neighbouring atom. Thus, is given the name 'donor'.