InAs quantum dots embedded into anti-modulation-doped GaAs superlattice structures

Abstract

Photoluminescence (PL) spectra of anti-modulation-doped GaAs superlattice structures containing thin InAs films of about 1-2.5 monolayers grown on semi-insulating (001)-oriented GaAs substrates at different temperatures are studied. The size distribution of InAs quantum dots (QD's) is found to be bimodal at the higher substrate growth temperature (TG = 505 °C) and is transformed into multimodal for the decreased growth temperature (TG = 420 °C) and growth interruption applied. For the first time we demonstrate the strong coupling between modes, which stabilizes the PL magnitude and the full width at half maximum of large index QD modes within a certain temperature interval (50-150 K) due to feeding of the radiative transitions from non-radiative decay and carrier transfer arising from decaying excitonic states of the low index QD mode.