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.