Negatively charged excitons in CdTe-based quantum wells: A time-resolved study

Using time-resolved photoluminescence, we have investigated the radiative behavior of neutral and negatively charged excitons in CdTe-based quantum wells. We find that the photoluminescence of negatively charged excitons can be well reproduced by a model of delocalized and thermalized three-particle complexes. A large radiative zone in k-space results from the transfer of the charged exciton momentum to the remaining electron (recoil effect). On the other hand, the photoluminescence decay of excitons is not well described in the framework of a model of delocalized and thermalized excitons. We infer that the main difference between the behavior of neutral and charged excitons in the time domain stems from the large radiative zone of charged excitons.