Temperature behavior of hot carrier dynamics in InP quantum dots

Photoluminescence (PL) kinetics of the InP self-assembled quantum dots is studied under quasiresonant optical excitation in the temperature range 10–100 K. It is found that the PL rise time abruptly drops with increasing temperature. The model calculations based on the rate equations have shown that this drop cannot result from thermostimulated phonon relaxation of the hot carriers. We developed a model assuming that the main reason for variations in the PL kinetics is related to thermal ejection ("evaporation") of holes from the quantum dots, with a fraction of the dots acquiring negative charge. The model allowed us to describe quantitatively the PL rise as well as the PL decay over the whole temperature range under study. We identified also a number of effects caused by electron evaporation from the quantum dots at temperatures above 60 K. Comparison of the results of the model calculations with the experimental data has allowed us to determine rate parameters of the ejection processes