Final answer:
In reverse bias, the electric field across a PN junction's depletion region is larger than at equilibrium, due to the widening of the depletion zone and increase in the potential energy barrier which impedes charge carrier movement.
Step-by-step explanation:
Understanding Reverse Bias in PN Junctions
When a PN junction is in reverse bias, the positive terminal is applied to the n-side, widening the depletion region and increasing the energy barrier height. This hinders the diffusion of holes across the junction, resulting in a larger electric field across the depletion region compared to the equilibrium state.
In reverse bias, the electric field produced by the uncovered ions is responsible for the potential energy difference across the p-n junction, which is increased. As a consequence, the electric field crossing the depletion region under reverse bias is larger than at equilibrium. The depletion region's resistance is significant, which contributes to the lack of current flow in the reverse bias configuration of a semiconductor diode.
The behavior of the semiconductor diode demonstrates its role as a one-way valve, allowing current to flow easily in forward bias but preventing it in reverse bias. This is essential in various applications, including audio amplifiers and computers, where diodes act as crucial components that control current direction and signal processing.