Question

Find the maximum wavelength of electromagnetic radiation which can create an electron - hole pair in silicon whose band gap energy is 1.1 $eV$.

• A. 560 $nm$
• B. 1130 $nm$
• C. 1240 $nm$
• D. 870 $nm$

Answer 1

The correct option is B 1130 $nm$


For the electron-hole pair creation, the energy of the incident radiation should be at least equal to the band gap of the material.
So,

$$E=\frac{hc}{\lambda }$$

$$\Rightarrow \lambda =\frac{hc}{E}=\frac{1242eV-\text{nm}}{1.1eV}$$

$$\Rightarrow \lambda \approx 1130\text{nm}$$