Conduction- and Valence-band Transport
Figure D.1 A very general semiconductor conduction band with an electron affinity that is a function of position. Such a situation could arise in an alloy semiconductor whose composition varies with position. The top of the conduction band is termed the local vacuum level. A constant, reference energy is shown.
We now turn our attention to the drift-diffusion formalism for modeling transport in semiconductors. In general, charge transport takes place in both the conduction-band electron and in the valence band in a semiconductor. The word semiconductor is used here and everywhere in this text ...