Specific features of luminescence spectra of ZnS : O and ZnS : Cu(O) crystals in the context of the band anticrossing theory

摘要

The anticrossing band theory, which specifies the change induced in the band structure by an isoelectronic impurity substantially distorting the lattice, is used to interpret the nature and specific features of the complex self-activated luminescence spectra of ZnS:O and ZnS:Cu(O). The light emission involving the self-activated luminescence centers SA and SAL, the spectral dependence of the emission components in relation to the content of dissolved oxygen, and the effects of the centers on the formation of bound excitons are considered. It is found that some absorption bands in the near-infrared spectral region are associated with the transitions between sublevels of the conduction band split in the presence of oxygen. On the basis of the experimental data, a heretofore unknown band model of ZnS:O is developed, and the Cu-induced modifications of the model are discussed. The effect of oxygen-containing agglomerates on the spectra is established. It is suggested that these agglomerates can be responsible for green emission from ZnS:Cu. The results complement the previously reported data of similar studies of ZnS:O and ZnS:Cu(O).