Optical Propeties of Cd_1-xCo_xIn₂Se₄ Single Crystals

Abstract

Cd1-x Co x In2Se4 (x=0.0, 0.01, 0.05, 0.10, 0.50) single crystals were grown by the vertical Bridgman technique. The grown single crystals have a pseudocubic structure. The optical energy gap of these single crystals has an indirect energy gap whereas its value is decreased with increases in composition x. The optical absorption peaks due to cobalt atoms are observed at each composition. It is suggested that the substituted cobalt atoms for cadmium atoms are located at T d symmetry of the CdIn2Se4 host lattice as Co2+ ions by the static crystal field theory. These peaks can be attributed to the electronic transitions between the split electron energy levels of Co2+ ions.