Identification of stable and metastable forms of VO2VO2 centers in germanium

Deep level transient spectroscopy (DLTS) together with first-principles calculations are used to investigate the centers that are formed upon annealing of the dominant VO center in Ge. It is suggested that as opposed to Si, the VO2VO2 complex in Ge is bistable and a double acceptor, with first and second acceptor levels 0.365 and 0.195 eV below the conduction band, respectively.