This video lecture discusses the lowering of the Fermi energy level
with decreasing temperature, providing mathematical insight into its temperature dependence, and explaining the energy-band diagram at T = 0 K. It also covers the distinction between degenerate and nondegenerate semiconductors, the effects of dopant freeze-out on the Fermi level at cryogenic temperatures, and the concept of Fermi potential including bulk Fermi potential under freeze-out conditions.