High quality ultrathin InAs/GaAs quantum wells grown by standard and low-temperature modulated-fluxes molecular beam epitaxy

Abstract

We report on the optical study of ultrathin (1-3 monolayers) InAs quantum wells in GaAs. The samples have been grown either by standard molecular beam epitaxy (MBE) or low-temperature (350°C) modulated-fluxes MBE. The latter technique enlarges the range of pseudomorphic deposition of strained InAs layers on GaAs. Both types of samples display sharp (down to 6 meV spectral width) and intense low-temperature excitonic photoluminescence, and a high in-plane homogeneity. Higher energy optical transitions have been observed in both absorption and photoluminescence excitation experiments, performed on multiple quantum well structures.