Optical investigation of microcrystals in glasses

CdS(x)Se(1-x) semiconductor-doped glasses are studied by means of optical techniques such as absorption, emission, and Raman spectroscopy in order to demonstrate the low dimensionality and quantization effects associated with the presence of CdS(x)Se(1-x) microcrystallites in the glass matrix. By applying simple models to our experimental results, it is possible from either absorption and luminescence or Raman spectra to calculate the effective dimension of microcrystals; these values very well agree with transmission electronic microscopy data. Moreover, by using a pump and probe technique, the authors have studied the absorption changes in CdS(x)Se(1-x) microcrystallites, resulting in the shift of the absorption edge and in the bleaching of the excitonic resonance when the pump intensity is increased.