Tight binding simulation of quantum electron transport in type II resonant tunneling devices

We report on calculations of quantum transport in an InAs/GaSb/AlSb (type II) based double barrier resonant tunneling diode. Our procedure uses a realistic band structure based on an empirical tight binding theory. In the formulation, an evanescent-wave matching at heterointerfaces as well as the conduction and valence-band-mixing effects, and the space charge effect are duly taken into account. Comparison has been made between our results and calculations using a two-band model which considers only the lowest conduction and the light-hole states. Our results show that current-voltage characteristics have an extra current peak due to significant heavy-hole mixing effects in the GaSb quantum well. It should be also noted that the matching of evanescent electron modes is essentially necessary to include the valley-mixing effects for the heterostructures, since breaking of a lattice-translational symmetry occurs at the interfaces.