Untersuchungen von Defektchalkopyrithalbleitern [vacancy] AB$_2$C$_4$ mit der Methode der gestoerten $\gamma-\gamma$- Winkelkorrelation (PAC)

The compounds [vacancy]AB$_2$C$_4$ with defect chalcopyrite structure are especially interesting among the ternary semiconductors. The reason is the occurrence of vacancies in an ordered and stoichiometric manner. Representatives of defect chalcopyrites have been implanted with radioactive probe isotopes mainly at the mass separator ISOLDE at CERN. The nuclear quadrupole interactions of the probe nuclei with the electric field gradients at lattice sites have been observed with perturped $\gamma-\gamma$ -angular correlation spectroscopy (PAC). The annealing of the implantation induced lattice damage takes place at temperatures in between 700 K and 1100 K in the substances investigated. $^{117}$Cd, $^{111}$In and $^{77}$Br substitute the Cd-site, both Ga-sites and the Se-site, resp., in CdGa$_2$Se$_4$. The probe $^{111}$Ag substitutes the vacancy. Both the experimentally and the theoretically determined electric field gradients are in the order of magnitude of 10E21 V/m$^2$. At elevated temperatures, disorder of the cation sublattices takes place. This can be monitored by PAC spectroscopy sensitively.