Calorimetric measurements of the enthalpies of formation and of mixing of II/VI and III/V compounds

A Calvet microcalorimeter capable of operating to 1000°C has been used with liquid metal solution techniques to measure the mixing enthalpies of InSb-GaSb, InSb-InAs, InAs-GaAs and CdTe-HgTe. In addition enthalpies of formation are reported for CdTe (−100830 ± 700 J/mol) and HgTe (−43600 ± 590 J/mol). During the work a novel method of stirring based on gentle pumping induced by a cyclic variation in pressure has been introduced with computer-based data logging. The results of this study have been used together with phase diagram and vapour pressure data to produce thermodynamic descriptions of the ternary phase diagrams which are in good agreement with experiment. (1, 2, 3, 4).