In Hg0.8Cd0.2Te crystals which had been grown by using the travelling heater method, a significant increase was observed in the carrier concentration of the last part to solidify. The carriers were identified as being Hg vacancies. The observed longitudinal vacancy concentration profiles could be quantitatively described in terms of a model which took account of the varying thermal history of the crystal along its length, and which assumed that the Hg vacancy diffusion coefficient was concentration-dependent. Overall, the diffusivity of Hg vacancies could be described by a pre-exponential factor of 0.002cm2/s and an activation energy of 1.6eV.

M.Neubert, F.M.Kiessling, B.Barz, K.Jacobs: Journal of Crystal Growth, 1993, 128[1-4], 604-8