Photoluminescence properties of highly excited CdSe quantum dots

Many-body effects were studied in highly photoexcited CdSe quantum dots (QDs). The size of the QDs was larger than the exciton Bohr radius in bulk CdSe crystals, so that the excitons are confined in the CdSe QDs. With increasing excitation density, the photoluminescence (PL) intensity increased linearly and was then saturated. In the intensity saturation regime, the blueshift and the broadening of the PL spectrum were observed. From a theoretical analysis including both exciton–exciton and carrier–carrier interactions, it was concluded that the PL intensity saturation originates from the deformation of the exciton wave function due to the quasi-Fermi-level generation.