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, electrons from the n-side cross to the p-side (where they are minority carriers) and holes from the p-side to the n-side, contributing to the diffusion current. Substituting values gives Crossing of carriers