Semiconductors Question 2
Question 2 - 2024 (01 Feb Shift 2)
Conductivity of a photodiode starts changing only if the wavelength of incident light is less than $660 nm$. The band gap of photodiode is found to be $\left(\frac{X}{8}\right) eV$. The value of $X$ is ;
(Given, $h=6.6 \times 10^{-34} Js, e=1.6 \times 10^{-19} C$ )
(1) 15
(2) 11
(3) 13
(4) 21
Show Answer
Answer: (1)
Solution:
$E _g=\frac{hc}{\lambda}=\frac{6.6 \times 10^{-34} \times 3 \times 10^{8}}{660 \times 10^{-9}} J$
$=\frac{6.6 \times 10^{-34} \times 3 \times 10^{8}}{660 \times 10^{-9} \times 1.6 \times 10^{-19}} eV$
$=\frac{15}{8} eV$
So $x=15$
