FIRST-PRINCIPLES ELECTRONIC-STRUCTURE OF CU-CENTERS IN CU-DOPED ZNS( LUMINESCENCE)

The electronic structures of various Cu+ luminescence centers in wurtz ite ZnS are studied by using first-principles linear muffin-tin-orbita l method combining atomic sphere approximation. The results for ZnS:Cu :CI and ZnS:Cu:Al show that Cu acceptor states are anomalously deep (b eyond 2.7 eV above the top of valence band) and located near the botto m of conduction band in these two cases. On the other hand, the result s for ZnS:Cu with sulfur vacancies manifest that the Cu+ center is an associated center, whose Cu d-like states are situated above the top o f valence band.