Preparation and characterization of CdS quantum dots doped phosphate nanocomposite glass

Design of a novel quantum dots doped glasses with high concentration semiconductor microcrystals is very important both for fundamental research of the quantum confinement of the exciting in semiconductor microcrystals in glass matrix and for potential applications in quantum communication, quantum computation, the new optoelectronic devices and so on, since high concentrations of the semiconductor microcrystals are expected to produce higher optical nonlinearities. In this paper, CdS quantum dots nanocomposite glass were successfully produced by phase precipitation of the oversaturated solid solution. The structural characterization which has been carried out by using X-ray diffraction (XRD) demonstrated microcrystals arising in the glass matrix and gave evidence of hexagonal structure of the microcrystals. Average size of the microcrystals and its distribution has been determined by using High Resolution Scan Electron Microscopy (HRSEM). HRSEM pictures clearly indicated that all crystallites of CdS are uniformly distributed in the glass matrix and their growth up to 10 nm Thermal treatment of the glass allows us to vary the size of the microcrystals. The optical characterization of the glasses was carried out by using a UV-Visible spectrophotometer and a fluorescence spectrophotometer. The results showed that the absorption edge shifted to the long wavelength as increasing the thermal treatment temperature or time implies that the crystal size increases with thermal treatment temperature or time. PL spectra exhibit well-defined peaks associated with band-edge luminescence and recombination at defects.