IDENTIFICATION OF THE CADMIUM VACANCY IN CDTE BY ELECTRON-PARAMAGNETIC-RESONANCE

The isolated cadmium vacancy in CdTe is identified by means of electron paramagnetic resonance (EPR) in its single negative charge state. The spectrum reveals that the defect has trigonal symmetry, which can be explained in a model in which the hole occupies a dangling-bond t2 orbital, and the orbital degeneracy is removed by a Jahn-Teller distortion. From the hyperfine interaction it is concluded that the hole is highly localized on one of the four tellurium neighbors. Photo-EPR measurements indicate that the 2 - / - acceptor level is situated less than 0.47 eV above the valence band.