Phase diagrams and thermodynamic descriptions for the Bi-Se and Zn-Se binary systems

The phase diagrams and thermodynamic basis for the Bi-Se and Zn-Se binary systems are analyzed in this work, where the CALPHAD technique is adopted and the associated solution model is applied for the liquid phase. Two binary associates, Bi2Se3 and ZnSe, are assumed to be present in Bi-Se and Zn-Se melts respectively. Bi3Se2, Bi2Se3 and ZnSe are treated as stoichiometric phases, while BiSe is described with the two-sublattice model in order to respect its large solubility. The Gibbs free energies of each phase are formulated in this work, which allow liquidus, enthalpies of mixing, activities, and enthalpies of formation and entropies of formation to be well represented, the results of which can provide fundamental information for semiconductor design. (C) 2014 Elsevier B.V. All rights reserved.