It was shown that positron annihilation could distinguish vacancies in the various sub-lattices of a binary compound. The Se vacancies, VSe, in N-doped material and the Zn vacancies, VZn, in Cl-doped material were identified on the basis of the shape of the core electron momentum distribution. The charge state of the defect which involved VSe was neutral, or negative, in p-type material thus suggesting that VSe was complexed with an acceptor. The concentration of the VSe complexes was greater than 1018/cm3; indicating that their role was important with regard to the electrical compensation of p-type ZnSSe.

K.Saarinen, T.Laine, K.Skog, J.Mäkinen, P.Hautojärvi, K.Rakennus, P.Uusimaa, A.Salokatve, M.Pessa: Physical Review Letters, 1996, 77[16], 3407-10