The number density of electrons and holes in pure silicon at $27^{\circ} \mathrm{C}$ are equal and i

Question

The number density of electrons and holes in pure silicon at $27^{\circ} \mathrm{C}$ are equal and its value is $2.0 	imes 10^{16} \mathrm{ml}^{-3}$. On doping with indium the hole density increases to $4.5 	imes 10^{22} \mathrm{~m}^{-3}$, the electron density in doped silicon is

Professor PC Thomas Classes · Answer

(b) : Using, $n_e n_A=n_i^2 \Rightarrow n_e ho=n_i^2$\ Here, $n_i=2 	imes 10^{16} \mathrm{~m}^{-3}, ho=4.5 	imes 10^{22} \mathrm{~m}^{-3}$ $ \  	herefore \quad n=\frac{n_i^2}{ho}=\frac{\left(2 	imes 10^{16}ight)^2}{4.5 	imes 10^{22}}=8.89 	imes 10^9 \mathrm{~m}^{-3} $