Abstract
The properties of a variety of imperfect AlSb/InAs heterostructures have been studied, using ab initio pseudopotential calculations to include a microscopic description of the interfaces themselves. Substitutional group IV defects were investigated at a number of lattice sites, acting as both donor and acceptor impurities. The interaction between silicon donor defects and the interfaces is shown to result in the formation of localized resonances that alter the optical and transport characteristics of the structures. The detailed form of the localized features is found to be sensitive to structural disorder close to the interfaces.