Explain the formation of the depletion region in a p-n junction and the effect of forward and reverse bias on it.

At the junction electrons from the n side and holes from the p side diffuse across and recombine, leaving behind immobile charged ions and a region depleted of free carriers, across which a potential barrier is set up. Forward bias opposes the barrier, narrows the depletion region and allows a large current; reverse bias reinforces the barrier, widens the region and allows only a very small leakage current.

No citable source has been recorded for this record. Treat it as practice material, not as fact.

Explanation

This asymmetry is what makes the junction rectify.