The effect of high-temperature annealing, in various Hg atmospheres, upon crystals with long or very-long infra-red cut-off wavelengths was studied. Undoped crystals were grown by using the travelling-heater method, with a Te solvent zone. The crystals were annealed at 500 or 550C under Hg pressures which ranged from Hg-rich conditions to Te-rich conditions. The samples were then either air-cooled or water-cooled to room temperature, and Hall effect measurements were carried out at 77K in magnetic fields of between 500G and 10kG. It was found that the hole concentration in the annealed crystals was approximately inversely proportional to the partial pressure of Hg; thus indicating that the material was essentially intrinsic at the annealing temperature. A defect model was presented, and the relationship between the mass-action constants of native acceptor defects in HgMnTe was deduced.

S.W.Kutcher, T.O.Pöhler, S.Trivedi, Z.Yu, H.R.Vydyanath, P.Becla: Journal of Electronic Materials, 1996, 25[8], 1383-7