OPTICAL-PROPERTIES OF CD4SNSE6 AND CD4SNSE6-CO2-CRYSTALS( SINGLE)

Cd4SnSe6 and Cd4SnSe6:Co2+ single crystals were grown by the chemical transport reaction method. The single crystals crystallize in a monocl inic structure and have the direct band structure. The optical energy gap is 1.68 eV for Cd4SnSe6 single crystal and 1.50 eV for Cd4SnSe6:Co 2+ single crystal at 293 K. Impurity optical absorption peaks due to t he doped cobalt in Cd4SnSe6:Co2+ single crystal were observed at 6250 cm-1, and 6131 cm-1 which separated from the peak at 6250 cm-1 were ob served at 80 K. These peaks are assigned to the electron transitions b etween the energy levels of Co2+ ion sited at the T(d) symmetry point in the Cd4SnSe6:Co2+ single crystal.