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 %.