Phase separation effects in AlGaAsSb/GaSb alloys

Layers of Al$_x$Ga$_{1-x}$As$_y$Sb$_{1-y}$ solid solutions on GaSb substrates were obtained by the MOVPE method. Three series of samples with an Al content of $x$ = 0.2, 0.27 and 0.45 and different $y$ content providing both positive and negative lattice matching with the substrate were studied. Analysis of Raman scattering spectra showed the presence of phase separation effects for both Group V (Sb–As) and Group III elements – a tendency towards preferential binding of As and Al atoms was detected.