Unified description of Cu-related luminescence processes in II–VI semiconductors

Abstract An empirical model of t 2 - and e-type one-electron levels is constructed, compatible with the energy-band scheme of the host material. A great variety of optical processes involving the charge states A°(Cu 2+ ) and A - (Cu + ) of the copper acceptor can thus be described, including several previously unrelated effects. Bound-exciton formation and annihilation are demonstrated to play an important role in various absorption and emission transitions. Alignment of the t 2 Cu level for ZnS and CdS leads to an evaluation of band discontinuities for these semiconductors.