Given, density of electron-hole pair in pure germanium =3×1016m−3 On doping, hole density =4.5×1022m−3 Electron density = ? We know n12=nhne Where ni is electron–hole density in pure semiconductor; nh is hole density; ne is electron density
⇒ne=
ni2
nh
=
(3×1016)
4.5×1022
=2×1010m−3
Therefore, electron density in doped germanium will be 2×1010m−3