Photoluminescence of ZnS:Cu crystals at various concentrations of copper

Doping of ZnS crystals with background impurities and ZnS:Al crystals by various concentrations of copper from a bismuth melt has been carried out. The photoluminescence spectra of the starting ZnS crystals annealed in the bismuth melt and doped by copper have been investigated. Interpretation of the experimental results according to the model in which the associates (Cu _Zn ^′ Cu _i ^● ) are responsible for the B-Cu band (≈460 nm) and the donor—receptor pairs [Cu _i ^● -(Cu _Zn ^′ Cu _i ^● )] are responsible for the G-Cu band (≈505 nm) is given. It is assumed that doping by copper from a bismuth melt is accompanied by the separation of a Cu_xS-type phase. It has been shown that heat treatment of ZnS crystals in the Bi melt does not lead to the appearance of luminescence centers based on Bi_Zn, Bi_S, and Bi_i. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 794–798, November–December, 2005.