P-n Junction: Equilibrium and Out of Equilibrium

This lecture covers the linearly graded junction geometry for the impurity profile of the p-n junction, deriving the built-in potential expression and introducing quasi-Fermi levels. It then explores the ideal current-voltage characteristic assumptions, illustrating the position-dependent minority carrier concentrations and current density flow through the device. The asymmetrical J-V curve is emphasized, showing current saturation for reversed biased junctions and exponential increase for forward bias. Numerical examples of current values are provided, along with discussions on space charge, fixed charges, and the characteristics of the p-n junction at equilibrium and out of equilibrium.