Carrier dynamics study of the temperature- and excitation-dependent photoluminescence of InAs/GaAs quantum dots

We investigate the effects that the carrier dynamics have on the temperature and excitation intensity dependence of the photoluminescence (PL) of self-assembled InAsGaAs quantum dot heterostructures having different size uniformities. We propose a rate equation model that takes into account the dot size distribution, the random population of density of states, and all of the important mechanisms of carrier dynamics, including radiative and nonradiative recombinations, thermal escaping and relaxing, and state filling effects. We used this model to simulate the PL spectra obtained from our samples; the results agree well with the measured data. We discuss in detail our quantitative calculations of the corresponding mechanisms of the thermal redistribution and state filling effects. These mathematical analyses provide distinct explanations for the phenomena we observed in the temperature- and incident power-dependent PL spectra of samples having different size uniformities.