Example: Calculate intrinsic carrier concentration for Ge at room temperature. \[ \begin{array}{ll} \mu_{\mathrm{e}}=3900 \mathrm{~cm}^{2} \mathrm{~V}^{-1} \mathrm{~s}^{-1} & \mu_{\mathrm{h}}=1900 \mathrm{~cm}^{2} \mathrm{~V}^{-1} \mathrm{~s}^{-1} \text { for } \mathrm{Ge} \\ \sigma_{\mathrm{Ge}}=2.2(\Omega . \mathrm{m})^{-1} & |\mathrm{e}|=1.6 \times 10^{-19} \mathrm{C} \text { or As } \end{array} \]