Growth of Cu(In,Ga)S2 single crystals using CsCl flux

Single crystals of Cu(In,Ga)S2 were successfully grown using CsCl flux in vacuum. The grown single crystals were typically 3-4 mm with unshaped form. The Cu(In,Ga)S2 single crystals with various Ga concentration were obtained by control of the Ga concentration in the starting materials. The optical band-gaps of obtained single crystals were estimated from the reflectance spectrum. The optical band-gap changed between 1.42 and 2.40 eV at room temperature with dependence on the Ga concentration.