OPTICAL-PROPERTIES OF UNDOPED AND CO-DOPED SBSBR AND BISBR SINGLE-CRYSTALS

SbSBr, BiSBr, SbSBr:Co and BiSBr:Co single crystals were grown by the Bridgman technique. The grown single crystals crystallize in an orthor hombic structure and have an indirect band structure. The temperature dependence of the optical energy gap for the single crystals shows ano malies at the first- and second-order phase transition points. Cobalt dopants are located at the T-d symmetry point in the host single cryst als as Co2+ and Co3+ ions. Impurity optical absorption peaks due to th e electron transitions between the energy levels of the Co2+ and Co3ions are observed.