The isolated Cd vacancy was identified, in its single negative charge state, by using electron paramagnetic resonance techniques. The spectrum revealed that the defect possessed trigonal symmetry. This could be explained by invoking a model in which the hole occupied a dangling-bond orbital, and in which the orbital degeneracy was removed by a Jahn-Teller distortion. On the basis of the hyperfine interaction, it was concluded that the hole was highly localized on one of the four Te neighbors. Photo-electron paramagnetic resonance measurements indicated that the 2-/- acceptor level was situated less than 0.47eV above the valence band.

P.Emanuelsson, P.Omling, B.K.Meyer, M.Wienecke, M.Schenk: Physical Review B, 1993, 47[23], 15578-80