Acceptor correlated centers in II-VI compounds

We have investigated the acceptor doping of CdTe and ZnSe to elucidate vari ous aspects of self-compensation. Before doping, a well-defined deviation o f the stoichiometry was adjusted by thermal pre-treatment of the bulk cryst als. We used ion implantation for doping. Radiation damage could be largely removed by proper annealing. Besides stable elements, we implanted radioac tive isotopes of accepters decaying into inactive centers (Ag-111 --> Cd, A s-73 --> Ge). On the other hand, we implanted native or isoelectronic isoto pes which transmute by radioactive decay into relevant dopants (Cd-107 --> Ag, Sr-85 --> Rb). In this way it is possible to avoid self-compensation. T he use of radioactive isotopes allows an unambiguous correlation of defect features occurring in electrical and photoluminescence measurements with th e 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.