Question

The responsivity of an InGaAs photodiode for the quantum efficiency of 70% (energy gap of lnGaAs is equal to 0.75 eV,) is​

Answer 1

Given:

Eg = 0.75 eV

η = 70%

To find:

R =?

Explanation:

According to Einstein energy formula,

$\displaystyle E_g = \frac{hc}{l}$

where

Eg = energy gap of a material

h = plank's constant

l = length of material

Put given values in above eq

0.75 = $\displaystyle \frac{6.64 \times 10^{-34} \times 3 \times 10^8}{l}$

∴ l = 1664$\times10^{-9$ m

Now, the responsivity in terms of efficiency is calculated by

R = $\displaystyle \frac{\eta \times l}{1248}$

   =  $\displaystyle \frac{0.70\times 1664\times 10^{-9}}{1248}$

R = 0.933 A/W

∴ The responsivity of an InGaAs photodiode is 0.933 A/W