The diffusivity of Hg vacancies in Hg0.8Cd0.2Te was deduced by using both the component of the Hg tracer diffusion coefficient which depended upon the Hg partial pressure, and thermodynamic data on equilibrium Hg vacancy concentrations over the entire region of existence of Hg0.8Cd0.2Te. It was found that the results could be described by:

D (cm2/s) = 0.002 exp[-0.44(eV)/kT]

By performing non-equilibrium diffusion experiments, a rapid stoichiometry change was detected by means of Hall effect measurements. The diffusion coefficient which was obtained in this way was found to be described by:

D (cm2/s) = 0.00075 exp[-0.46(eV)/kT]

and depended upon the Hg vacancy diffusivity. The fast component of the Hg tracer diffusion coefficient had been used for the initial estimation, although it had been shown that it was due to dislocation or sub-grain boundary diffusion. However, the good agreement between the above values indicated that the theory which was used could reasonably be applied to the data.

M.Neubert, K.Jacobs: Journal of Crystal Growth, 1996, 161, 229-33