Correlation between the structural and optical properties of polydispersed II-VI quantum dots in glass matrix

We report the results of a systematic investigation of the structural and optical properties of polydispersed semiconductor microcrystals in glass. Transmission electron microscope experiments reveal the existence of microcrystals of different radii and size dispersion around the average radius. A simple method is proposed to extract the structural parameters by the Gaussian deconvolution of the size histogram. The presence of a polydispersed dot distribution accounts very well for the observed absorption spectra which exhibit different excitonic features corresponding to the estimated microcrystal sizes. The linewidth of the low temperature photoluminescence spectra is satisfactorily explained by a simple emission-broadening model based on the effective mass approximation which takes into account the dispersion of the quantum dot radius obtained by the transmission electron microscope experiments.