Thermal Analysis of Chemical Reaction Process Forming CuInSe₂ Crystal

Abstract

In order to establish the preparation method of high-quality CuInSe 2 single crystals, we have investigated the chemical reaction process of CuInSe 2 by differential thermal analysis and by powder X-ray diffraction measurements. It is confirmed that CuInSe 2 compound undergoes a phase transition from chalcopyrite to sphalerite structure at 815°C and melts at 996°C. In the chemical reaction process of a Cu+In+2Se mixture, an explosive exothermic reaction occurs at 250°C, which is ascribed to the formation of intermediate products of the In-Se system. In the chemical reaction process of a CuIn+2Se mixture, an explosive selenization reaction forming CuInSe 2 compound occurs at 575°C. It is concluded that the selenization of CuIn alloy at temperatures higher than 600°C suppresses the formation of lattice defects and heterogeneous products.