Excitation intensity and thickness dependent emission mechanism from an ultrathin InAs layer in GaAs matrix

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Epitaxy, photoluminescence spectroscopy, heterostructures, emission spectroscopy, semiconductors, excitons, correlated electrons, x-ray diffraction


A set of samples containing a single ultrathin InAs layer with varying thickness from 0.5 to 1.4ML in a GaAs matrix have been grown by molecular beam epitaxy on GaAs (001) substrates at low temperatures and investigated by low-temperature photoluminescence (PL). A linear change in emission energy with InAs thickness has been experimentally observed. The PL emission line shape from InAs/GaAs heterostructures has been investigated as a function of incident optical intensity. The interplay between uncorrelated electron-hole pairs, free excitons, and localized excitons, as a function of the excitation intensity, is found to play a significant role on the optical properties of the InAs layer and is described in detail.