Question:
Consider a situation in which reverse biased current of a particular P-N junction increases when it is exposed to a light of wavelength $\leq 621 \mathrm{~nm}$.
During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly.
Correct Option: 1
Solution:
Band gap $=\frac{h c}{\lambda_{0}}$
$\lambda_{0} ;$ threshold wavelength
Band gap $=\frac{1242 e \mathrm{ev}-\mathrm{nm}}{621 \mathrm{~nm}}=2 \mathrm{eV}$