PHXII14:SEMICONDUCTOR ELECTRONICS- MATERIALS- DEVICES AND SIMPLE CIRCUITS
365201
A \(pn\) photodiode is fabricated from a semiconductor with a band gap of \(2.5\,eV\). The signal wavelength is:
1 \(6000\) \( \mathop A^{~~\circ} \)
2 \(6000\,nm\)
3 \(4000\,nm\)
4 \(5000\) \( \mathop A^{~~\circ} \)
Explanation:
\(E_{g}=\dfrac{h c}{\lambda} \Rightarrow \lambda=\dfrac{6.6 \times 10^{-34} \times 3 \times 10^{8}}{2.5 \times 1.6 \times 10^{-19}}\)
\( \Rightarrow \lambda = 4.95 \times {10^{ - 7}}\;m \approx 5000\mathop {{\rm{ }}A}\limits^{\;\;^\circ } .\)