Formation and optical properties of ZnSe and ZnS nanocrystals in glasses

•Zinc blended ZnSe nanocrystals were precipitated in silicate glasses.•Hexagonal wurtzite ZnS nanocrystals were precipitated in borosilicate glasses.•Both ZnSe and ZnS nanocrystals showed broad-band visible emission upon excitation.

ZnSe and ZnS nanocrystals (NCs) were precipitated in glasses through heat-treatment. High resolution transmission electron microscope image confirmed that ZnSe NCs were formed in the silicate glasses, and the X-ray diffraction patterns confirmed that ZnS NCs were precipitated in the borosilicate glasses. Absorption shoulders of the ZnSe NCs and ZnS NCs appeared at ~ 2.76 eV and ~ 3.78 eV, corresponding to the bandgap energies of bulk ZnSe and ZnS crystals, respectively. Instead of the intrinsic emissions, broad-band visible photoluminescence from the surface defects or color centers in the glasses was observed from these ZnSe or ZnS NCs.