The temperature‐composition phase diagram of the HgTeHgI₂pseudobinary system on the HgTe rich side

Abstract

The temperature‐composition phase diagram of the HgTeHgI2 system was determined from 0 to 45 Mol‐% HgI2 between 25 and 670°C using Debye‐Scherrer powder X‐ray diffraction techniques and differential thermal analysis. Solid solutions of HgTe and HgI2 with the cubic, zinc blende‐type structure exist above 300°C, having a maximum solubility of 11.7 ± 0.8 Mol‐% HgI2 in HgTe at 501 ± 5°C. The known monoclinic compound Hg3Te2I2 is formed by a peritectic reaction upon cooling at 501 ± 5°C, with the peritectic point at approximately 37 ± 4 Mol‐% HgI2.

The Temperature-Composition Phase Equilibria in the Hg0.8Cd0.2Te-HgI2 Pseudobinary SystemBased on part of a thesis to be submitted by M. A. Hutchins to the Graduate School of Rensselaer Polytechnic Institute in partial fulfillment of the requirements for a Ph.D. degree.Dedicated to Professor Welf Bronger on the Occasion of his 70th Birthday

“…This value is significantly greater than the above mentioned solubility of HgI 2 in HgTe [18]. The observations of this work are compared to those of the earlier investigations of the related CdTe-HgI 2 [17], HgTe-HgI 2 [18,19] and of the preliminary studies [21] of the present system. The present investigation of the Hg 0.8 Cd 0.2 Te-HgI 2 temperature-composition phase diagram is mainly concerned with the region between 0 and 40 mole-% HgI 2 .…”

“…During the latter investigation [19], the formation of the previously unknown cubic phase Hg 3 TeI 4 was observed, the structure of which was recently determined [20]. This value is significantly greater than the above mentioned solubility of HgI 2 in HgTe [18]. This value is significantly greater than the above mentioned solubility of HgI 2 in HgTe [18].…”

“…The further purification of HgI 2 by repeated sublimation has been discussed earlier [18]. The further purification of HgI 2 by repeated sublimation has been discussed earlier [18].…”

“…The Hg 0.8 Cd 0.2 Te-HgI 2 samples for the X-ray diffraction studies were prepared similarly as described earlier for the HgTe-HgI 2 system [18]. Mixtures of pulverized Hg 0.8 Cd 0.2 Te and HgI 2 with a total mass of about one gram were sealed in cleaned [22] and outgassed [23] fused silica ampoules (4 mm I.D., 6 mm O.D., 27Ϫ34 mm I.L., Ͻ 0.4 ml free volume) under a vacuum of 10 Ϫ5 torr or less with the source material end of the ampoule immersed in liquid nitrogen.…”

“…Several sets of such ampoules were prepared, in which the compositions of the starting mixtures ranged from pure Hg 0.8 Cd 0.2 Te to pure HgI 2 in 0.5, 1, 2, 3, 4, and 5 mole-% HgI 2 increments. The annealing times used are sufficient for the samples to reach equilibrium, based on the earlier studies of the solubility of HgI 2 in HgTe [18,19] and in Hg 0.8 Cd 0.2 Te [21], and based on diffusion rate estimations. In order to reduce the equilibration time, some samples were initially annealed above their final temperature for up to three days.…”