Photocarrier recombination in AlyIn1−yAs/AlxGa1−xAs self-assembled quantum dots

Abstract

Ensembles of self-assembled quantum dots (QD’s) are investigated using photoluminescence (PL) and resonant time-resolved PL in the visible spectrum. Faster carrier relaxation/recombination dynamics (∼250 ps) are observed for resonant excitations. The influence of the temperature and the intensity of excitation is also measured by monitoring sharp spectral features (∼200 μeV) obtained when probing the PL of small ensembles (∼600 QD’s). Temperature-independent linewidths are observed up to 70 K (${\mathit{k}}_{\mathit{B}}$T≫200 μeV). For higher excitation intensity, however, the collective background, emitted by the ensemble of QD’s, is enhanced relative to the amplitude of the individual sharp spectral features.