Practice question

**Depletion region** also called space-charge region, thickness typically 0.5 μm, contains no mobile carriers, only fixed ions, negative on p-side, positive on n-side, diffusion current due to concentration gradient, drift current due to field, equilibrium when J_drift + J_diff =0, voltage drop mainly across depletion region. In reverse bias, the applied voltage ( V ) adds to the built-in potential ( V₀ ), increasing the effective barrier height to V₀ + V . Substituting values gives V₀ + V, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.