Power density and temperature effects on the photoluminescence spectra of InAlAs/GaAlAs quantum dots

Photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurement techniques are used to characterize the size and the density of In1−xAlxAs/Ga0.67Al0.33As quantum dots (QDs) for different QD aluminium compositions. The integrated photoluminescence intensity (IPL) depends on an excitation light power, decreases with increasing the aluminium proportion emphasizing the QDs surface density decreasing. In TRPL experiments, the influence of QD lateral coupling is evidence in high QD density sample, the radiative lifetime increases with increasing temperatures for sample with a low aluminium proportion, instead, the observed radiative lifetime keep constant for samples with a high aluminium proportions in agreement with the QD zero-dimensional confinement.