Positron annihilation studies were made of films which had been grown, by vacuum evaporation at 220C, onto both plain glass and oxide-coated glass substrates. By monitoring the linearity of the valence annihilation parameter as a function of the core annihilation parameter, a method was found for analyzing the data which showed directly that the same vacancy defect could be present in all of the films. By comparing the core annihilation parameter at the defect, to that at the VCd vacancy, this defect was identified as being the di-vacancy, VCd-VTe. Its concentration in the films decreased from about 1018 to less than 1016/cm3 during annealing in air (400C, 0.5h). It was noted that Cl-doping seemed to stabilize the di-vacancies.

L.Liszkay, C.Corbel, L.Baroux, P.Hautojärvi, M.Bayhan, A.W.Brinkman, S.Tatarenko: Applied Physics Letters, 1994, 64[11], 1380-2