Thermodynamic Modeling of the Bi-Se and Bi-Te Binary Systems

Abstract

Thermodynamic descriptions of the Bi-Se and Bi-Te systems have been developed using the CALculation of PHAse Diagrams (CALPHAD) method based on the experimental data available in the literature. The liquid phases were described by the associated solution model for the Bi-Se and Bi-Te systems with Bi₂Se₃ and Bi₂Te₃ as associates, respectively. The intermetallics Bi₂Se₃, Bi₃Se₄, Bi₈Se₉, BiSe, Bi₈Se₇, Bi₄Se₃, Bi₃Se₂, Bi₄Te₅, Bi₈Te₉, BiTe, Bi₄Te₃, Bi₂Te and Bi₇Te₃ were treated as stoichiometric compounds while Bi₂Te₃ was modeled by the sublattice model based on its homogeneity range and crystal structure. A set of self-consistent thermodynamic parameters for the Bi-Se and Bi-Te systems was obtained. Comparisons between the calculated results and experimental data available in the literature show that the most reliable experimental information can be satisfactorily accounted for by the present modeling.