PARTIAL PRESSURES OF HG AND TE-2 OVER (HG1-XZNX)1-YTEY SOLID-SOLUTIONS

The partial pressures of mercury PHgand of diatomic tellurium P2have been determined from the optical density of the vapor phase coexisting with HgTe-ZnTe solid solutions containing 10, 20, 30, 50, and 70 mol % ZnTe. The optical density was measured between 250 and 750 nm, the maximum temperature range covered was 300 to 791 °C. The predominant vapor species is pHg, even for the Te-saturated state. Only pHg was measurable for the metal-saturated state. The maximum value was measured for 50 mol % ZnTe and is 34 atm at 727 °C. At temperatures up to about 500 °C, PHgis very nearly the same for all of the metal-saturated samples studied. For the Te-saturated state, both PHgand P2were measured. A plot of log PHgagainst 1000/T is a straight line at low temperatures and at a given temperature, pHg is higher the smaller the mol % ZnTe in the solid solution. The chemical potential of HgTe in the solid solutions is derived from the data and compared to that in HgTe-CdTe. © 1990, American Vacuum Society. All rights reserved.