THE TEMPERATURE-COMPOSITION PHASE-DIAGRAM AND THE MISCIBILITY GAP OF HG1-XCDXTE SOLID-SOLUTIONS BY DYNAMIC MASS-LOSS MEASUREMENTS

The dynamic mass-loss technique has been employed to measure Hg partia l pressures over Te-saturated Hg1-xCdxTe solid solutions with x = 0.40 , 0.54, and 0.70 in the 10(-1) to 10(-4) atm range. The relative chemi cal potentials of HgTe in Hg1-xCdxTe solid solutions have been calcula ted using the measured Hg partial pressures at temperatures below 413 degrees C, and fitted into an analytical expression. A Gibbs-Duhem int egration yielded the relative chemical potentials of CdTe. By combinin g the relative chemical potentials of the binary components HgTe and C dTe, an expression for the Gibbs free energy of mixing was derived. Th e binodal (miscibility gap) and spinodal curves of the Hg1-xCdxTe soli d solutions have been established with the critical temperature and co mposition of 221 degrees C and Hg0.40Cd0.60Te.