Selenium solubility in solid zinc selenide

Abstract

Selenium solubility in solid s-ZnSe (F43m) under mono- and divariant equilibrium conditions has been determined by a direct physicochemical method in the temperature range 850–1173 K. The maximum concentration of excess selenium is 3.76 × 10^–4 mol of excess Se per mole of ZnSe at 1173 K. The homogeneity range of the s-ZnSe phase has been shown to be characterized by retrograde solubility at its Se-rich phase boundary. A model has been proposed for defect formation in nonstoichiometric s-ZnSe at temperatures in the range 963–1173 K and pSe₂ pressures in the range 1.0⁵ × 10^]4 to 5.01 × 10⁵ Pa according to which the dissolution of excess Se is accompanied by the formation of electrically neutral associated vacancy defects in the zinc sublattice.