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The optical properties of lattice-matched GaAsSb/InGaAs/InP heterostructures with a varying InGaAs layer thickness (0–900 Å) were investigated. These structures display strong low temperature type II luminescence, the energy of which varies with the InGaAs layer thickness and ranges from 0.453 to 0.63 eV. The type II luminescence was used to determine directly and accurately the conduction band offset of these structures. The values obtained herein are 0.36 and 0.18 eV at 4.2 K for the GaAsSb/InGaAs and GaAsSb/InP heterojunctions, respectively, with the GaAsSb conduction band higher in energy.

We present a study of interface roughness scattering in not-intentionally-doped AlSb/InAs/AlSb quantum wells grown by molecular beam epitaxy on [001] GaAs semi-insulating substrates. The low-temperature mobility is found to be limited by interface roughness scattering for well widths below 100 Å. The measured mobilities are well accounted for by Gold’s theoretical treatment [A. Gold, Phys. Rev. B 35, 723 (1987)], once it is suitably modified to account for the band nonparabolicity of InAs. The experimental electron density dependence of the mobility indicates a lateral correlation length for the interface roughness Λ≊62 Å for interface fluctuations approximately 1 monolayer high. We believe this roughness scale is characteristic of the bottom (InAs-on-AlSb) interface.

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