No abstract

CuAl 2 S 4 single crystals were grown with the constituent elements copper, aluminium and sulphur (purity 6N) as the starting material by the chemical transport reaction method using iodine as a transport agent. Layer-type colourless transparent single crystals were obtained, and the crystal structure of the single crystals was found to be cubic with the lattice constant a = 9.954 Å. The energy bandgap of the CuAl 2 S 4 single crystal was revealed to be direct bandgap, and the optical energy gap was found to be 4.10 eV at 10 K.