Copper-indium-gallium-sulfide-selenide (CIGSSe) is used in photovoltaic cells and photocathodes, because of its tunable optoelectronic properties, but the fabrication of CIGSSe samples usually requires a multistage process under vacuum. Herein we used a flux growth technique for the sulfide system and achieved efficient flux growth of idiomorphic copper-indium-sulfide CuInS2 crystals of size ∼5 μm from a NaCl-InCl3 flux under mild conditions at ambient pressures. We first examined the flux growth conditions such as holding temperature, solute concentration, and holding time for growing highly crystalline CuInS2 crystals. A moderate holding temperature (∼550 °C) and high solute concentration (∼70 mol %) yielded idiomorphic pure CuInS2 crystals. High-resolution transmission electron microscopy showed clear electron diffraction spots, indicating that the resultant CuInS2 crystals had a highly crystalline, intrinsic tetragonal crystal structure. Thermogravimetry-differential thermal analysis showed that the CuInS2 crystals grew efficiently during flux evaporation at 550 °C, at which the flux evaporation degree reached ∼81%. The CuInS2 crystal growth mode is discussed based on the characterization results.
ASJC Scopus subject areas
- 化学 (全般)