Question

A semiconductor has equal electron and hole concentration of $4 \times 10^{8} m ^{-3}$. On doping with a certain impurity, the electron concentration increases to $3.2 \times 10^{9} m ^{-3}$, then the new hole concentration of the semiconductor is ________$\times 10^{6} m ^{-3}$.

Answer 1

$n _{ e } n _{ h }= n _{ i }^{2}$
$\therefore 3.2 \times 10^{9} \times n _{ h }=16 \times 10^{16}$
$\therefore n _{ h }=50 \times 10^{6} m ^{-3}$