Miscibility gaps and spinodal decomposition in III/V quaternary alloys of the type A x B y C1−x−y D

Abstract

Thermodynamic concepts have been developed for the calculation of solid‐phase miscibility gaps and spinodal decomposition in quaternary alloys of the type A_xB_yC_1−x−yD. These concepts have been applied to the analysis of III/V quaternary alloys using the delta‐lattice‐parameter (DLP) solution model. In addition, the effects of coherency strain energy have been included in the calculation. Results are presented for the systems Al_xGa_yIn_1−x−yP, Al_xGa_yIn_1−x−yAs, InP_xAs_ySb_1−x−y, and GaP_xAs_ySb_1−x−y. Even though these systems all have miscibility gaps, they are shown to be stable against spinodal decomposition at all temperatures due to the elastic strain energy inherent in coherent decomposition of single crystalline alloys.