EFFECT OF CADMIUM TO SULFUR RATIO ON THE PHOTOLUMINESCENCE OF CDS-DOPED GLASSES

In order to determine the origin of the long-wavelength photoluminescence spectra of CdS-doped glasses, luminescence spectra from glasses doped with CdS(x) having various Cd to S ratios were examined. The intensity of the luminescence peak decreased with increasing sulfur content, which indicates that the luminescence could be associated with sulfur-deficient trap centers. With the shift of the band gap of CdS, to lower energy by crystal growth, the peak position of the trap-center-related luminescence also shifted to tower energy. The ratio of these two energy shifts indicates that the trap center is donorlike, not acceptorlike. The shape of this luminescence band was dependent on the excitation wavelength, which indicates that more than two types of trap centers exist in the glass.