Acceptor Correlated Centers in II-VI Compounds

Abstract

We have investigated the acceptor doping of CdTe and ZnSe to elucidate various aspects of selfcompensation. Before doping, a well-defined deviation of the stoichiometry was adjusted by thermal pre-treatment of the bulk crystals. We used ion implantation for doping. Radiation damage could be largely removed by proper annealing. Besides stable elements, we implanted radioactive isotopes of acceptors decaying into inactive centers ( 111 Ag 3 Cd, 73 As 3 Ge). On the other hand, we implanted native or isoelectronic isotopes which transmute by radioactive decay into relevant dopants ( 107 Cd 3 Ag, 85 Sr 3 Rb). In this way it is possible to avoid self-compensation. The use of radioactive isotopes allows an unambiguous correlation of defect features occurring in electrical and photoluminescence measurements with the incorporated dopants. Under optimum pre-and post-implantation annealing conditions, we find an almost one-to-one doping efficiency with respect to the implanted dose.