Polyassociative thermodynamical model of A2B6 semiconductor melt and phase equilibrium in Cd-Hg-Te system: Optimization of the thermodynamical functions of the model and quasi-binary structural diagram of Cd-Hg-Te system

Abstract

Within the frames of the model of the polyassociative solutions the comparative analysis was performed of the formation parameters of multi-atom complexes in CdTe and Hg-Te systems. It was shown, that thermodynamical properties of the studied systems can be described in the supposition of the presence in the liquid phase of the ATe, A 2 Te 3 , ATe 2 , A 2 Te (A = Cd, Hg) and free Te, Cd, Hg atoms. In accordance with the model of polyassociative solutions the data on p-T-x equilibrium in the region of quasi-binary cross-section of Cd-Hg-Te system structural diagram were obtained. It was shown, that the mixing effects in the three-component liquid phase are satisfactorily described by the formation of CdHgTe and CdHgTe 3 associates. The good correspondence of the calculations and experiment in the high temperature part of the Cd-Hg-Te system structural diagram was achieved.

Isothermal growth kinetics of CdxHg1-xTe LPE layers

“…The data on p−T−x phase equilibria in the system are supposed to be the main information while choosing the conditions of the crystallization process. For this system, the investigation of phase equilibria within the model of polyassociated solutions, which takes into account the presence of a set of complexes in the liquid phase, was started by us in [1,2]. That's why, to increase the reliability of a thermodynamic information taken from the theoretical analysis, the kinetic assumptions about the phase formation process in the ternary system need to be developed.…”

“…The thermodynamic functions necessary for obtaining the boundary concentrations, which correspond to the conditions of phase equilibria in the Cd-Hg-Te system, were borrowed from our works [1,2], where these parameters were found within the model of polyassociated solutions. The calculation of molar densities of the liquid phase enriched by tellurium and those of the Cd x Hg 1-x Te solid solution was carried out using thermodynamic data [8].…”