Hot Excitons Contribution into the Photoluminescence of Self-Assembled Quantum Dots in CdSe/ZnSe Heterostructures under Different Excitation Conditions

"We present experimental and theoretical study of the photoluminescence in a set of double asymmetric CdSe/ZnSe quantum wells with self-assembled quantum dots separated by rather thick ZnSe barrier. It is found that for a certain ratio between depths of quantum wells hot exciton channel in the photoluminescence excitation spectrum of shallow well is dominant up to the energy interval exceeding 10 longitudinal optical phonons above the bottom of the exciton zone of the ZnSe. A model of the electrons, holes, and excitons transfer within the system of asymmetric quantum wells is developed. We demonstrate that the prevailing of the exciton channel is due to different rate of transitions between quantum wells of excitons and single charge carriers".