Temperature effects on the radiative recombination in InAlAs/GaAlAs quantum dots

The influence of the temperature has been studied in self-assembled InAlAs/GaAlAs quantum dots (QDs) using photoluminescence (PL) and time-resolved PL (TRPL). With increasing temperature, the exciton retrapping in QDs, after a thermal activation, is evidenced and confirmed by a narrowing of the PL spectrum width, and an increase of the PL decay time. From the temperature dependence of the integrate PL signal, the activation energy is estimated at 110 meV, in agreement with the electronic state in QD and wetting layer (WL) determinate by PL spectroscopy measurements. The influence of the QD size on the QD confinement energy, is also observed in the evolution of the decay time with temperature and detection energy.