Luminescence of ZnWO 4 crystals with oxygen introduced

Abstract

The results of studying the spectral characteristics of the photo- and cathodoluminescence of zinc tungstate crystals subjected to heat treatment in an oxygen atmosphere or irradiation with high-energy oxygen ions are presented. The introduction of oxygen leads to a decrease in the
efficiency of photoluminescence. In addition, the introduction by heat treatment leads to a change in the excitation spectrum. It is assumed that the observed change in the characteristics of photoluminescence is due to the destruction of complexes formed during crystal synthesis, including glow centers. During heat treatment in an oxygen atmosphere, the destruction of emitting complexes occurs at a depth comparable to the penetration depth of exciting photons. A sharp decrease in the
efficiency of luminescence excitation with increasing energy of exciting photons is explained by the presence of a concentration gradient of oxygen entering the diffusion and, accordingly, of destroyed emitting complexes. An assessment was made of the oxygen entry depth; the characteristic entry depth was 20 nm when processed for 7 hours at 900 ◦ C.