Methodology of abrupt heterostructures: Band diagram calculations

A methodology for calculating the energy band diagrams of abrupt heterostructures using the band discontinuities and the interface charge density as parameters is presented. The calculations are based on two basic equations which are universally accepted - the lineup of the bands relative to the common Fermi level (which embodies the valence band discontinuity) and the charge neutrality (which embodies the interface charge density). The two equations, with the aid of Poisson's equation, yield the total band bending on each side of the interface and the dependence of the energy bands on the position (i.e. the band diagram). The methodology is illustrated for the HgTe-CdTe semimetal-semiconductor heterostructure, and demonstrates the interplay of band offsets and interface charges in establishing the nature of a heterostructure (either rectifying or ohmic) and in determining the potential barrier height, for both n-type and p-type CdTe. The methodology presented in this study is general and can be applied to additional semiconductor-semiconductor and semimetal-semiconductor heterostructures.