Question

In a p-n junction under equilibrium, there is no net current.

Hint:

Under equilibrium conditions, the diffusion current of charge carriers is exactly balanced by the drift current due to the electric field, resulting in no net current in a p-n junction.

Answer 1

Upon p-n junction formation, electrons from the n-type region migrate to the p-type region, and holes from the p-type region migrate to the n-type region. This migration establishes a depletion region devoid of free charge carriers.
Consequently, an electric field emerges across the depletion region, counteracting further charge carrier diffusion. This equilibrium state is achieved when the drift current (induced by the electric field) precisely balances the diffusion current, resulting in zero net current flow across the junction.