A modified mass-loss measurement technique was used for the direct  in situ  monitoring of metal vacancy formation in (Hg1-xCdx)1-yTey, where x was equal to 0.2 or 0.4. In the former case, the metal vacancy concentrations were determined, at temperatures of between 336 and 660C, for 3 different compositions (y) within the homogeneity region. These values ranged from 2.4 x 1019 to 6.8 x 1019/cm3. The formation enthalpy of a singly-ionized metal vacancy was deduced to be between 0.17 and 0.45eV; depending upon the deviation from stoichiometry. When x was equal to 0.4, three samples with different y-values gave metal-vacancy concentrations ranging from 1.9 x 1019 to 5.5 x 1019/cm3 at temperatures of between 316 and 649C. The enthalpy of vacancy formation was between 0.25 and 0.40eV. When compared with data on HgTe, these results revealed a slight but significant decrease in the enthalpy of vacancy formation in going from HgTe to Hg0.8Cd0.2Te. This supported theoretical predictions of the bond-weakening effect of Cd in the latter system. On the basis of the simultaneously determined equilibrium Hg partial pressure within the homogeneity range, vacancy concentration versus partial pressure isotherms were constructed. The Hg partial pressures were also measured along the 3-phase boundaries of solid solutions with both x = 0.2 and x = 0.4. These values were in close agreement with published data which had been obtained by means of optical absorption measurements.

The Direct Determination of the Vacancy Concentration and P-T Phase Diagram of Hg0.8Cd0.2Te and Hg0.6Cd0.4Te by Dynamic Mass-Loss Measurements. H.Wiedemeier, Y.G.Sha: Journal of Electronic Materials, 1990, 19[8], 761-72