The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased…

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because
  1. fractional change in majority carriers produce higher forward bias current
  2. fractional change in majority carriers produce higher reverse bias current
  3. fractional change in minority carriers produce higher forward bias current
  4. fractional change in minority carriers produce higher reverse bias current

Solution

In photo–diode, the diode is connected in reverse bias, so initially the current will be very small. If the light is incident on the diode, its photons produce more minority charge carriers, which are called photo-generated charge carriers, due to which the reverse current increases.

In reverse bias, the width of the depletion region is more and the current is already very small, So the fractional charge in the current due to the light will be large.

Asked in: JEE Main 2022 (25 Jun Shift 1)

Practice more Semiconductors questions on Aicharya