A study of the solid-vapor equilibrium in HgTe is performed. The experimental ( P H , T, x) diagram is given, where ( P H is the mercury vapor pressure, T the temperature of the solid and x the concentration of extrinsic charge carriers. The results can be interpreted by assuming the presence of one structural defect at low temperatures ( T < 350°C)—probably Frenkel defects—and the occurrence of another defect above 350°C. The energy of formation of Frenkel defects W F = 0.50 eV, and the energy of transfer of an interstitial mercury to the vapor W R = 0.19 eV, are deduced from low-temperature results. These equilibrium constants allow to build a theoretical ( P H , T, x) diagram, which is in agreement with experimental results on n-type samples ; the interpretation of results on p-type samples leads to a determination of the electron-to-hole mobility ratio : b≅ 65 at 77°K. The particular results for T > 350°C and the observed dependence of the Hall constant with magnetic field are also discussed. The intrinsic carrier concentration is determined between 20°K and 350°K.
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