PREPARATION AND OPTICAL-PROPERTIES OF SOL-GEL DERIVED ZNSE CRYSTALLITES DOPED IN GLASS-FILMS

Borosilicate glass films nominally containing up to 40 wt% ZnSe semiconductor crystallites have been successfully prepared on silica glass substrates by the sol-gel process. The influence of heat treatment on optical absorption, emission, and excitation properties was studied. On heating the films at temperatures from 500 to 750-degrees-C in a hydrogen atmosphere, small ZnSe crystallites with an energy gap varying from 2.93 to 2.63 eV are formed, giving a strong emission with a peak ranging from 540 to 630 nm that is attributed to Se-vacancy defects of the crystallites. The redshift of the emission peak, with respect to the energy pp, is independent of particle size, remaining at around 0.65 eV. The size of the crystallites is estimated to range from 2.8 to 9.5 nm.