Spinodal decomposition ranges of Al$_x$Ga$_{1-x}$N$_y$P$_{1-y}$ and Al$_x$Ga$_{1-x}$N$_y$Sb$_{1-y}$ alloys

Abstract

Spinodal decomposition ranges of low $N$-content Al$_x$Ga$_{1-x}$N$_y$P$_{1-y}$ and Al$_x$Ga$_{1-x}$N$_y$Sb$_{1-y}$ alloys grown on GaP (001) and GaSb (001) substrates, respectively, are described. The alloys are considered according to the strictly regular approximation. In the analysis we take into account the transformations of the bonds and strain, coherency strain, and elastic energies. The spinodal decomposition ranges of the alloys with compositions $0\le x\le0.4$, $0\le y\le0.05$ are demonstrated up to temperatures of 1100$^\circ$C. It is shown that the enlargement of Al and N concentrations dramatically increases the phase separation temperature.