Practice question

**p-n junction formation** diffusion of holes from p to n and electrons from n to p leaves ionized donors positive on n-side and acceptors negative on p-side, forming space-charge depletion region with electric field directed from n to p (positive to negative), barrier potential V_b ≈0.3 V Ge, 0.7 V Si, opposes further diffusion, drift current due to minority carriers swept by field balances diffusion at equilibrium net current zero. In forward bias, the applied voltage mostly drops across the depletion region due to its high resistance, with negligible drops across the p-side and n-side. Substituting values gives Depletion region, which matches expected behaviour for