INTRINSIC CARRIER RELAXATION AND THE EXCITON LIFETIME IN INAS GAAS QUANTUM DOTS/

The carrier relaxation in self-assembled InAs/GaAs quantum dots (SADs) is investigated by photoluminescence spectroscopy (PL) at resonant ex citation (below the GaAs and the wetting layer bandgap). Different rel axation paths are observed in the InAs/GaAs quantum dot system and all ow to identify the hole relaxation in the SADs as multiphonon assisted tunneling. The PL decay time in the SADs after resonant excitation (a bout 600 ps) is attributed to the lifetime of the quantum dot exciton. In agreement with theoretical predictions, we find a constant lifetim e of about 600 ps for temperatures below 50 K and a linear increase of the lifetime between 50 and 100 K with a slope of 26 ps/K.