A steady-state thermal model for carrier dynamics in self-organized InAs/GaAs quantum dot heterostructure is presented. The effect of quantum-dot size distribution, density of states random population, thermal emission, retrapping, and relaxation are investigated. The temperature-dependent photoluminescence spectra obtained from two samples with different dot densities and size uniformities are simulated in this model and show a good agreement with experiment. The corresponding mechanisms of carrier dynamics related to the thermal redistribution and lateral transition of excited carriers as well as the observed phenomena resulting from these mechanisms, are discussed in detail. (c) 2005 American Vacuum Society.