Question

A diode allows the electric current to flow, when it is in forward bias, but if it is in reverse bias it will not allow the electric current to flow. Why?

Answer 1

In forward biasing of diode, the depletion width at the p-n junction is very thin and its potential barrier is low. Thus the charge carriers easily move across the depletion region and hence diode conducts electric current in forward biasing.

Whereas in reverse biasing, the depletion width at the p-n junction is thicker than that in forward biasing and its potential barrier is large. Thus the charge carriers cannot move across the depletion region and hence diode does not conduct electric current in reverse biasing.