Synthesis and X-ray Powder Diffraction Study of Alloys in the As 2 Se 3 -InSe System

Phase equilibria in the As 2 Se 3 –InSe system were studied by physicochemical analysis methods (differential thermal, X-ray powder diffraction, and microstructural analyses and microhardness and density measurements), and the phase diagram of the system was constructed. It was found that the system is a quasi-binary section of the ternary system In–As–Se and is characterized by the formation of two ternary selenides, InAs 2 Se 4 and In 3 As 2 Se 6 , melting without decomposition at 775 and 810°C, respectively. The coordinates of eutectic points are (13 mol % InSe, 315°C), (80 mol % InSe, 675°C), and (85 mol % InSe, 535°C). The arsenic selenide-based glass-forming range is 20 mol % InSe, and the crystalline-glass range extends to 35 mol % InSe. The solubilities based on As 2 Se 3 and InSe are limited and are 5 and 3 mol %, respectively. According to X-ray powder diffraction analysis data, the compounds InAs 2 Se 4 and In 3 As 2 Se 6 crystallize in the tetragonal system with the unit cell parameters a = 9.44 Å, c = 8.73 Å, V = 785.6 Å 3 , Z = 4 and a = 9.42 Å, c = 8.77 Å, Z = 3, respectively.