A p-n photodiode is made of a material with a band gap of $2.0 \mathrm{eV}$. The minimum frequency of the…
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
$10 \times 10^{14} \mathrm{~Hz}$
$5 \times 10^{14} \mathrm{~Hz}$
$1 \times 10^{14} \mathrm{~Hz}$
$20 \times 10^{14} \mathrm{~Hz}$
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, $h v=2.0 \mathrm{eV}$
$\text {or } v=\frac{2.0 \times 1.6 \times 10^{-19}}{6.6 \times 10^{-34}} \approx 5 \times 10^{14} \mathrm{~Hz}$