Chemical reaction process and the single crystal growth of CuInS_2 compound

摘要

In order to establish the preparation method of high-quality CuInS_2 single crystals, we have investigated the chemical reaction process by means of differential thermal analysis and powder X-ray diffraction measurements. In the chemical reaction process of a Cu＋ In＋2S mixture, an explosive exothermic reaction occurs at 640 deg C, which is ascribed to the formation of products of the In-S system. In the case of a CuIn＋2S mixture, an explosive sulfurizaiton reaction occurs at about 700 deg C, leading to the CuInS_2 phase. The melting point decreases by 17 deg C under S vapor pressure increasing from 200 Torr to 8 atm. The formation of heterogeneous products are greatly suppressed by the sulfurization of CuIn alloy at temperatures higher than 750 deg C. In conclusion, high-quality bulk single crystals can be grown by the sulfurization horizontal Bridgeton method with controlling S vapor pressure.