Exciton dark states in the recombination kinetics of InAs quantum dots

Time-resolved photoluminescence experiments in high quality InAs/GaAs quantum dots clearly show theinterplay between radiative recombination and thermalization processes. In particular from temperaturedependent PL spectra, we prove that the carrier recombination dynamics is ruled by the thermal populationin optically inactive exciton states, related to the population of the first excited hole levels. Moreovertime-resolved spectra do not show any relaxation bottleneck, indicating an efficient carrier capture and afast energy relaxation of the photogenerated carriers