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. The space-charge region, formed by immobile ionized impurities after carrier diffusion, is called the depletion region due to the absence of free charge carriers. Substituting values gives Depletion region, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.