Formation process of Cd and Zn chalcogenide-doped glasses via gels containing thiourea or selenourea complexes

摘要

Abstract: The formation process of glasses doped with cadmium and zinc sulfide or selenide microcrystallites has been studied, along with the characterization of the glasses obtained. Sulfide microcrystallite-doped SiO$-2$/ glasses were prepared by the heat-treatment at around 400$DGR@C of gels in which thiourea complexes were confined. The formation of thiourea complexes of Cd(NO$-3$/)$- 2$/ and Zn(NO$-3$/)$-2$/ in the starting solutions to form gels was confirmed from IR and Raman spectra. The crystalline phase of microcrystallites doped was hexagonal for CdS and cubic for ZnS and their mean diameter varied with the amount of thiourea complexes added. The absorption edges of the semiconductor-doped glasses were found to be shifted to shorter wavelengths in reference to those of corresponding bulk semiconductors due to the quantum size embedded in gels only in the presence of L($PLU@)-ascorbic acid as an antioxidant. Most of Se in the gels, however, was found to be lost within forming selenides of the heat-treatment, though the complexes themselves produced cubic CdSe or ZnSe by the heat-treatment at around 400$DGR@C in air.!16