Q. A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly
A) ${10 \times 10}^{14}$ Hz
B) ${5 \times 10}^{14}$ Hz
C) ${1 \times 10}^{14}$ Hz
D) ${20 \times 10}^{14}$ Hz
Explanation
(b) p-n photodiode is a semiconductor diode that produces a significant current when illuminated. It is reversed biased but is operated below the breakdown voltage.
Energy of radiation = band gap energy
i.e., $h$v = 2.0 eV
or v = $\frac{{2.0 \times 1.6 \times 10}^{- 19}}{{6.6 \times 10}^{- 34}} \approx {5 \times 10}^{14}$ Hz
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.