DEEP IMPURITY STATES AND INTRINSIC DEFECTS IN PHOTOREFRACTIVE CD1-XFEXTE CRYSTALS

Studies were made of the low-temperature optical and photoelectric pro perties of Cd1 - xFexTe crystals (x = 0.0038) which provided informati on on the optical quality of these crystals and the nature of their in homogeneity, and also revealed deep Fe2+ impurity centers and singly c harged acceptor complexes. It was established that these complexes, wh ich include doubly charged cadmium vacancies and ionized donors, are a nisotropic. It was shown that their anisotropy is determined by the na ture of the donor atom and its position in the crystal lattice (at a c ationic or anionic site). Since these crystals contain real deep impur ity centers and acceptor complexes, a mechanism is proposed for the ph otorefractive effect in these crystals. It was observed for the first time that the photorefractive properties of CdTe crystals containing i mpurity 3d elements may exhibit anisotropy unrelated to that of the el ectrooptic effect. (C) 1998 American Institute of Physics.