Systematic study of type II Ga1-xInxSb/InAs superlattices for infra-red detection in the 10-12 μm wavelength range

We perform a systematic study of the factors governing the optical properties of type II Ga1-xInxSb/InAs superlattice structures. We map the parameter space corresponding to the layer widths, alloy concentrations and interface bonding types, and identify those structures for which the fundamental gap lies in the desired range for device application. In addition, we examine the higher lying miniband energies to assess the structures for favourable Auger recombination limits. The microscopic interface bonding configuration is shown to have a significant impact upon the magnitude of the fundamental gap? and confirms the requirement for full-bandstructure calculations in the evaluation of possible structures. We study the features of the optical spectra for those structures whose bandstructures are recognized as most suitable for detector applications.