Radiative recombination in photoexcited quantum dots up to room temperature: The role of fine-structure effects

We demonstrate dominant radiative recombination in high-quality self-assembled quantum dots all the way up to room temperature. This allows a proof of the theoretically predicted characteristic doubling of the radiative recombination time with increasing temperature, entirely caused by fine-structure effects. Over the whole temperature range, the transient decay of the photoluminescence can be described by temperature-independent radiative decay rates of dark and bright excitons, respectively, taking into account a thermally activated interplay between dark and bright states and dark-exciton accumulation.