Optical properties of undoped and Co2+-doped MgGa2S4 single crystals

MgGa₂S₄ and MgGa₂S₄:Co²⁺ single crystals were grown by the closed tube sublimation method. The optical energy gaps of the MgGa₂S₄ and the MgGa₂S₄:Co²⁺ single crystals were found to be 3.31 eV and 2.98 eV, respectively, at 300 K. Impurity optical absorption peaks in the MgGa₂S₄:Co²⁺ single crystal originated from the electronic transition between the energy levels of the Co²⁺ ion sited in Cs symmetry. In the photoluminescence spectrum at 10 K of the MgGa₂S₄ single crystals, a blue emission peaking at 405 nm and a broad red emission centered at 607 nm were observed.