Synthesis of ZnGa2Se4 by the Reaction of GaI3 and ZnI2 with Selenium

The thermodynamic modeling of the GaI3–Se and ZnI2–Se systems was carried out by the equilibrium constant method in the temperature range of 200–500°C. The equilibrium degrees of conversion of iodides to Ga2Se3 and ZnSe were found to be 21 and 0.7%, respectively. Molecular iodine was the major component of the vapor phase in both systems. A preparation method of Ga2Se3, ZnSe, and ZnGa2Se4 by the reaction of GaI3 and ZnI2 with selenium in an evacuated quartz reactor with two temperature zones was developed. The selective withdrawal of iodine from the reaction melt made it possible to attain a practical yield of selenides of 86–90% at 450°C. The residual content of iodine in the products was 0.2–1 at %.