Question

In a photodiode, the conductivity increases when the material is exposed to light. It is found that the conductivity changes only if the wavelength is less than 620 nm. What is the band gap ?

Answer 1

Band gap = Energy need to over come the gap

$=\frac{hc}{\lambda }=\frac{1242eV-nm}{620nm}$

$=2.0eV$