Question

Why does depletion layer decrease in forward bias?

Answer 1

Depletion region

1. It is a thin layer on both sides of a P-N junction that has immobile ions in the absence of charge carriers.

Forward bias

1. A P-N junction is said to be forward-biased if the negative terminal of the battery is connected to N-side and the positive terminal is connected to the P-side.
2. In forward bias, the voltage drop across both sides of the P-N junction is small.
3. During forward bias, the built-in electric field and applied electric field are in opposite directions.
4. So their resultant will be less than the built-in electric field. Thus a thinner and less resistive depletion layer is created.

Thus, the depletion layer decrease in forward bias.