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

NEET 2008

Exam: NEET
Year: 2008
Subject: Physics
Chapter: Semiconductors

NEET 2008 · Physics · Semiconductors

A p-n photodiode is made of a material with a band gap of 2.0 eV ....

A p-n photodiode is made of a material with a band gap of

2.0 \mathrm{eV}

. The minimum frequency of the radiation that can be absorbed by the material is nearly

Options

A $10 \times 10^{14} \mathrm{~Hz}$
B $5 \times 10^{14} \mathrm{~Hz}$
C $1 \times 10^{14} \mathrm{~Hz}$
D $20 \times 10^{14} \mathrm{~Hz}$

Correct answer

B. $5 \times 10^{14} \mathrm{~Hz}$

Step-by-step solution

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 ie,

h v=2.0 \mathrm{eV} \text{ or } v=\frac{2.0 \times 1.6 \times 10^{-19}}{6.6 \times 10^{-34}} \approx 5 \times 10^{14} \mathrm{ Hz}

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