Luminescence investigations of highly-strained layer InAs-GaAs superlattices.

We describe photoluminescence investigations in InAs-GaAs superlattices in the thin-layer limit (10-20 A). The data, which are compared to theoretical results obtained from band structure calculations, yield an estimate of the conduction band discontinuity of 550 meV at the interfaces. They also show that, although the superlattice has a bandgap (765 meV) close in energy to that of the corresponding bulk In(.5)Ga(.5)As alloy (800 meV), the bandstructures are very different. In the superlattice, electrons and light holes appear to be the important carriers, and they tend to be spatially separated, to the extent that this is meaningful in the thin layer limit.