ELECTRONIC-STRUCTURE OF INGAAS AND BAND OFFSETS IN INGAAS/GAAS SUPERLATTICES

We report the results of self-consistent density functional calculations using ab initio pseudo-potentials on InxGa1-xAs/GaAs superlattices for x = 0.25, 0.5, 0.75 and 1.0. The calculations were performed for two strained configurations. It was found that for GaAs substrates the valence band offset was almost independent of In content. For the case of InxGa1-xAs substrates, the valence band offset appears to vary non-linearly with the amount of strain in the GaAs layer. As a precursor to obtaining the band offsets, the electronic band structure of InGaAs was calculated for different compositions and strain conditions. These results are analysed and compared with experiment.