The nature and the energy structure of impurity and intrinsic defects, including the formation of anisotropic impurity centers, were determined in V-doped semi-insulating Cd1-xHgxTe (x ≤ 0.037) crystals which were grown by the Bridgman technique for the first time. From detailed analysis of the spectral dependence of the photo-diffusion current data obtained for the different directions of light propagation in crystals, as well as the impurity absorption spectra, it was established that - for the investigated crystals - anisotropic V2+ and V3+ centers were formed. Two mechanisms of the electron photo-generation from the ground impurity state to the conduction band (direct photo-ionization and auto-ionization from the excited state V2+ ions) were established. It was shown that the efficacy of the auto-ionization of electrons depends on the position of the excited state relative to the conduction band bottom. The photo-induced impurity centers were formed as a result of the illumination of the crystals with the light with energy about 1.50eV. The nature and photo-ionization energy of these photo-induced centers were determined. The scheme of the impurity and intrinsic defects energy levels in the energy gap of the investigated crystals was presented.

Nature and Energy Structure of Impurity and Intrinsic Defects in V-Doped Cd1-xHgxTe. Y.P.Gnatenko, I.O.Faryna, P.M.Bukivskij, O.A.Shigiltchoff, R.V.Gamernyk, S.Y.Paranchych: Semiconductor Science and Technology, 2005, 20[5], 378-88