Formation of CdS/Cd1−xZnxS sandwich-structured quantum dots with high quantum efficiency in silicate glasses

CdS/Cd1−xZnxS sandwich-structured quantum dots (QDs) were precipitated in silicate glasses with high quantum efficiency up to 53%. The QDs were composed by a CdS core with a Cd1−xZnxS shell of about 1-3 nm in thickness through heat-treatment at 550 °C for 10 h. With the increased heat-treatment temperature, the intensity ratio between the intrinsic emission and the defects emission increased and the Stokes shift decreased from 84 to 4 meV, which was caused by both the increased size and passivated surface defects of the QDs.