A study of luminescence centers related to copper and oxygen in ZnSe

The effects of deviation from stoichiometry and the copper and oxygen concentrations on cathodoluminescence spectra were studied in ZnSe condensates obtained by chemical vapor deposition and doped with Cu during growth. The results were supplemented with the study of the microstructure and microcomposition using scanning electron microscopy, measurements of electrical conductivity, and calculations of the equilibrium between the native point defects. It is shown that three types of Cu-related centers are always accompanied with self-activated centers that include oxygen at the Se lattice site (O-Se). The paired centers SA(I)-Cu(I), SAL(II)-Cu(II), and III-Cu(III) are typical of all II-VI compounds. All observed I-III Cu-containing centers are associative. Models of emission centers are suggested. A change of the emission type I-III is related to the recharging of the same group of defects that include O-Se, Zn(Cu), and V-Zn. New phenomena that occurred in the region of I-III bands and were related to the profound purification of the material were observed. (C) 2001 MAIK "Nauka/Interperiodica".