On the phase diagram of solid solutions of the InAs-GaAs system

The purpose of the work has been the plotting of liquids and solids lines for a InAs-GaAs system by means of the differential thermic analyses, and the performing of the thermodynamic analysis. Specimens of InAs-GaAs solid solutions have been obtained by the method of chemical transport reactions. Based on the study of thermograms plotted, the solid and liquid temperatures for the InAs-GaAs solid solutions are obtained. The performed thermodynamic analysis of the phase equilibriums in the InAs-GaAs system allows to determine the interaction parameters for liquid and solid phases. The calculation of solid and liquid lines for the InAs-GaAs system studied has been performed by the NAIRI-3 computer. From the known values of the interaction parameters for the liquid and solid phases the activity coefficients for liquid and solid phases are calculated. The calculation is performed by the equations: 1nγsub(InAs)=[(kosup(l)+αx)x2]/(RT) and 1nsub(γ)GaAs=[(kosup(l)+αx)(1-x)2]/(RT). As the calculated heat of components mixing in solid phase is positive, solubility in the solid state must be limited, the upper critical temperature being Tsub(k)=kS/2R. For the InAs-GaAs system it is 5050K. Shown in the figures is the calculated border of the mutual solubility for the InAs-GaAs system in the solid state. (author)