Exciton dark states in the recombination kinetics of InAs quantum dots

Time-resolved photoluminescence experiments in high quality InAs/GaAs quantum dots clearly show the interplay between radiative recombination and thermalization processes. In particular from temperature dependent PL spectra, we prove that the carrier recombination dynamics is ruled by the thermal population in optically inactive exciton states, related to the population of the first excited hole levels. Moreover time-resolved spectra do not show any relaxation bottleneck, indicating an efficient carrier capture and a fast energy relaxation of the photogenerated carriers. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)