Practice question

**Diode characteristics** forward bias reduces barrier, width of depletion region decreases, resistance low ~10-100 Ω, current primarily due to majority diffusion, exponential I = I_s(e^{eV/kT}-1), reverse bias widens depletion region, resistance high ~MΩ, dominant current drift due to minority carriers, reverse saturation current small μA-nA, typically 10⁻⁶ A, increases sharply at breakdown Zener/avalanche. Drift current results from the electric field in the depletion region, moving electrons from p-side to n-side and holes from n-side to p-side, opposing diffusion at equilibrium. Substituting values gives Electric field, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.