Physics - Semiconductors Question with Solution | TestHub

Given: Density of Si atoms $=4\times 10^{28}$ atoms $/{\mathrm{m}}^3$ After doping with $1\mathrm{ppm}$ of Sb, $\begin{array}{rl}\text{ No. of Sb atoms }& =\frac{4\times 10^{28}}{10^6}\\ & =4\times 10^{22}\end{array}$ The above number of $\mathrm{Sb}$ atoms donates 1 electron each. $\therefore$ The total number of free electrons will be $4\times 10^{22}{\mathrm{m}}^{-3}$