Optical properties of MnAl2S4 and MnAl2Se4 single crystals

MnAl2S4 and MnAl2Se4 single crystals were grown by the chemical transport reaction method. Optical energy gaps of the MnAl2S4 and MnAl2Se4 single crystals were 3.75 and 3.21 eV, respectively, at 300 K. Emission peaks due to donor-acceptor pair recombinations were observed at 450 and 603 nm in the MnAl2S4 single crystal and at 488 and 655 nm in the MnAl2Se4 single crystal. Optical absorption peaks and emission peaks described as appearing due to Mn2+ ion sited in Td symmetry were observed at 414, 450, 482, and 527 nm in the MnAl2S4 single crystal and at 416, 455, 488, and 532 nm in the MnAl2Se4 single crystal.