Deep impurity states and intrinsic defects in photorefractive Cd1−x FexTe crystals

AbstractStudies were made of the low-temperature optical and photoelectric properties of Cd_1−x Fe_xTe crystals (x=0.0038) which provided information on the optical quality of these crystals and the nature of their inhomogeneity, and also revealed deep Fe²⁺ impurity centers and singly charged acceptor complexes. It was established that these complexes, which include doubly charged cadmium vacancies and ionized donors, are anisotropic. It was shown that their anisotropy is determined by the nature of the donor atom and its position in the crystal lattice (at a cationic or anionic site). Since these crystals contain real deep impurity centers and acceptor complexes, a mechanism is proposed for the photorefractive effect in these crystals. It was observed for the first time that the photorefractive properties of CdTe crystals containing impurity 3d elements may exhibit anisotropy unrelated to that of the electrooptic effect. Fiz. Tverd. Tela (St. Petersburg) 40, 1216–1220 (July 1998)