Topic: Electronic Devices
The conductivity of the intrinsic germanium at $300^{\circ}K$ is
When $n_{i}$ at $300^{\circ}K=2.5\times10^{13}/cm^{3}$ and $\mu_{n}$ and $\mu_{p}$ in germanium are 3800 and 1800 $cm^{2}/Vs$ respectively.
- A. 0.224 S/cm
- B. 0.0224 S/cm
- C. 2.24 S/cm
- D. 0.00224 S/cm
Answer: B. 0.0224 S/cm
Explanation: $\sigma=(n\mu_{n}+p~\mu_{p})q$. For intrinsic semiconductor $\sigma=(\mu_{n}+\mu_{p})n_{i}q$, where $n=p=n_{i}$. Therefore, $\sigma = (3800+1800)\times2.5\times10^{13}\times1.6\times10^{-19} = 0.0224~S/cm$.