Effects of epitaxial strain and ordering direction on the electronic properties of GaSb/InSb and InAs/InSb superlattices

The structural and electronic properties in common-anion GaSb/InSb and common-cation InAs/InSb [111] ordered superlattices have been determined using the local-density total-energy full-potential linearized augmented plane-wave method. The influence of the ordering direction, strain conditions, and atomic substitution on the electronic properties of technological and experimental interest (such as energy band gaps and charge carrier localization in the different sublattices) were determined. The results show an appreciable energy band-gap narrowing compared to the band gap averaged over the constituent binaries, either in [001] ordered structures or (more markedly) in the [111] systems; moreover energy band gaps show an increasing trend as the substrate lattice parameter is decreased. Finally, the systems examined offer interesting opportunities for band-gap tuning as a function of the growth condition (about 0.7 eV in GaSb/InSb and 0.3 eV in InAs/InSb).