Semiconductor junction terminology: In a PN junction, what is the name of the region near the interface that has been depleted of majority carriers due to diffusion and built-in electric field?

Introduction / Context:
The depletion region is central to diode operation. It forms at the PN junction due to diffusion of carriers and the resulting space-charge region. Understanding this region explains why diodes conduct asymmetrically and how reverse-bias widens the barrier while forward-bias narrows it.

Given Data / Assumptions:

• A standard PN junction at equilibrium.
• We are naming the carrier-depleted area at the interface.
• Terminology distinguishes physical region (depletion region) from quantities like barrier potential.

Concept / Approach:
Carriers diffuse across the junction until an electric field builds that opposes further diffusion. This leaves behind fixed ionized donors and acceptors, creating a region depleted of mobile majority carriers. The electric field across this region establishes the built-in potential (barrier) that must be overcome for forward conduction.

Step-by-Step Solution:
Initial diffusion: electrons move into p-side, holes into n-side.Space charge forms: immobile ions remain, creating an internal field.Depletion region exists where mobile carriers are scarce.Forward bias shrinks it; reverse bias expands it.

Verification / Alternative check:
Energy-band diagrams and capacitance–voltage measurements (junction capacitance decreases with reverse bias) confirm widening of the depletion region with increased reverse voltage.

Why Other Options Are Wrong:
Barrier potential: that is the voltage associated with the internal field, not the region name.n region / p region: refer to bulk material types, not the depleted interface zone.

Common Pitfalls:
Using “barrier potential” and “depletion region” interchangeably. One is a voltage; the other is a physical space.

Final Answer:
depletion region