SOLID-STATE PHASE-DIAGRAM OF THE ZINC SELENIDE CADMIUM SELENIDE SYSTEM

By examining the ion exchange processes Cd2+ --> Zn2+ in the ZnSe powder/melt (or solution) system, structures and phase relations in the temperature range 100 divided by 700-degrees-C were investigated, and the boundaries describing the equilibria between the zinc-blende and wurtzite CdxZn1-xSe solid solutions were determined. The temperature of the zinc-blende-to-wurtzite structural phase transition in CdSe (95+/-5-degrees-C), and enthalpies of structural transitions in CdSe ( 480+/-80 J/mol ) and in ZnSe ( 1050+/-100 J/mol ) were defined. CdxZn1-xSe solid solutions of both modifications obey a regular solution model. The solid-state phase diagram calculated from defined thermodynamical parameters agrees well with the experimental data.