Point defects in electrooptic oxides

Abstract

The defect physics of electrooptic oxides, belonging to the perovskite, LiNbO₃ and sillenite families is reviewed. Similarities and differences in defect behaviour are stressed. The role of point defects in the microscopic mechanisms for the photochromic and photorefractive effects is remarked. Attention is paid to the location of impurities in the lattice, state of charge, coupling to other defects and relaxation effects. The information on intrinsic point defects, mostly oxygen vacancy centres, relies on two main production methods: high temperature reduction and particle irradiation. Comparison between these two procedures and their effect on the various crystal structures is emphasized. Finally, self-trapping of carriers in these oxides to form small-polaron centres is also examined.