Question

A p-n photodiode is made of a material with a band gap of $2.0eV$. 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. $20\times {10}^{14}Hz$

Answer 1

Answer: (B)

$5\times {10}^{14}Hz$

p-n photodiode is a semiconductor diode that produces a significant current when illuminated with sufficient frequency of radiation. For absorbing minimum frequency of radiation the condition is given below,
Energy of radiation = band gap energy
i.e., $hv=2.0eV$
or $v=\frac{2.0\times 1.6\times {10}^{-19}}{6.6\times {10}^{-34}}\approx 5\times {10}^{14}Hz$