Electronic structure of strained-layer AlAs/InAs (001) superlattices

Abstract

(001) superlattices containing 15 principal layers of AlAs and either one or two of InAs have been grown by atomic-layer molecular-beam epitaxy on undoped (001) GaAs substrates. The samples, between 0.1 and 0.3 μm thick, have been studied by photoluminescence, electroreflectance, and piezoreflectance and monitored by phonon Raman-scattering spectroscopy and x-ray diffractometry. An empirical tight-binding model, combined with surface Green-function matching, is used to discuss the experimental data. An overall picture is obtained for the electronic structure of these superlattices with a valence-band offset close to 0.5 eV, which is consistent with the observed spectra.