Thermal annealing of self-assembled CdZnSe quantum dots studied by photoluminescence spectroscopy

Self assembled CdZnSe quantum dots (QDs) embedded in a ZnSe matrix were thermally annealed and the induced interdiffusion between Zn and Cd atoms was investigated by photoluminescence spectroscopy. We observed a blue shift of the QD emission by more than 100 meV. According to a Fickian diffusion model an activation energy of 2.2 eV for the interdiffusion of Cd and Zn between the CdZnSe QDs and the ZnSe barrier is determined. The half widths of the emission lines decrease significantly with increasing annealing temperature, which allows to observe in the spectrum of strongly interdiffused CdZnSe quantum dots a second emission peak. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)