THE ROLE OF CATION VACANCIES IN EXCITATION MECHANISM OF RE-IONS IN ALKALINE-EARTH SULFIDES

The VUV-excitation spectra and thermostimulated emission for intrinsic and impurity luminescence of alkaline-earth sulphides doped by cerium have been investigated. The intensity of activator emission is higher in samples with artificially created cation vacancies. The role of ca tion vacancies is displayed as a result of the common analysis of the temperature dependence of impurity luminescence with the curves of the thermostimulation of the hole traps created due to the presence of th e cation vacancies. For room temperatures the hole traps on cation vac ancies become unstable. Therefore the trap level of cation vacancy ser ves as a bridge for the capture of holes from the valence band to 4f R E level.