Structure and morphology evolution in mechanochemical processed CuInS2 powder

CuInS2 powders were synthesized by mechanochemical process from copper, indium and sulfur powders. A self-propagating combustion occurred during the milling process. Phase structure, morphology evolution and component uniformity of Cu-In-S system have been studied by X-ray diffraction, scanning electron microscope and energy dispersive analysis, respectively. Optical property of ball milled CuInS2 has been detected by UV-Vis spectroscopy. The results show that there is no intermetallic phase was observed before the self-propagating combustion though morphology changed obviously during this stage. The detected composition of mixed powder converges toward the original proportion with increased milling as the particle sizes decreased. Homogeneous CuInS2 particles less than 5 μm are obtained after milling 120 min. The reason of mechanically induced self-propagating reaction occurs during milling in this system is also discussed. The UV-Vis absorption spectrum shows the milled CuInS2 has a broad absorption over the entire visible light and extending into the near-infrared region and its band gap is 1.52 eV.