The formation mechanism of Cd-S-Se quantum dots with CdSe/CdS core-shell structure within silicate glass

The formation mechanism of Cd-S-Se quantum dots (QDs) with a CdS/CdSe core-shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd-S-Se QDs as a function of the heat-treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single-phased QDs was heat-treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd-S-Se QDs within the glass matrix, Cd-S-Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD-embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core-shell-structured QDs within silicate glasses is suggested.