ANNEALING STUDIES OF UNDOPED HG1-XMNXTE BULK CRYSTALS AT HIGH-TEMPERATURES

The effect of high temperature annealing treatments in varying mercury atmospheres on Hg1-xMnxTe crystals with lang wavelength infrared/very long wavelength infrared cut off wavelengths has been studied. The un doped Hg-1-x MnxTe crystals were grown using the traveling heater meth od with a tellurium solvent zone, and composition was verified by infr ared transmission measurements. The crystals were subjected to anneali ng temperatures of 500 and 550 degrees C under mercury pressures varyi ng from Hg-rich conditions to Te-rich conditions. The samples were eit her air cooled or water cooled to room temperature. Hall effect measur ements were carried out at 77K at magnetic fields varying from 500 Gau ss to 10 kGauss. The hole concentration in the annealed crystals was f ound to be roughly inversely proportional to the partial pressure of H g indicating that the material is essentially intrinsic at the anneal temperature. A defect model and a relationship between the mass action constants for the native acceptor defects of HgMnTe are presented.