Ionization potentials, electron affinities, and band offsets

Abstract

In hopes of relieving some of the confusion regarding band offsets at semiconductor heterojunctions, the problem is addressed from a simple, fundamental thermodynamics point of view. It is noted that one form of an ‘‘electron affinity rule’’ can be stated which is exact and rigorous, but not very useful. A modified form of the electron affinity rule, in which the effect of electrostatic fields at the surface are to be excluded from experiment or not calculated from theory, can be stated which is almost rigorous and generally useful.