PN Junctions: Equilibrium and Band Diagrams

This lecture discusses the behavior of p-n junctions at equilibrium, focusing on the Fermi energy and the depletion zones on both sides. The instructor explains how applying voltage affects the Fermi energy and the height of the barrier, leading to changes in the depletion region. The lecture covers the calculation of the depletion width and the junction capacitance, emphasizing the relationship between the built-in voltage and the external voltage applied. The instructor provides a checklist for drawing band diagrams of p-n junctions, illustrating the differences between p-n and Schottky diodes. The lecture concludes with an analysis of ideal diode currents, detailing how major and minority carriers behave under different voltage conditions, including passing and blocking polarization. The concepts of current generation and recombination in the depletion region are also addressed, providing a comprehensive understanding of the dynamics within p-n junctions.