Structural characterization of AlxGa1−xSb grown by LPE

AlxGa1−xSb ternary solid solutions lattice-matched to the GaSb (001) substrate with composition in the range 0.05≤x≤0.2 were grown by liquid phase epitaxy. High resolution X-ray diffraction and Raman scattering techniques were applied to characterize AlxGa1−xSb alloys. The out of plane lattice parameter was estimated directly from the asymmetrical diffractions of planes (115) and (−1−15). The out of plane lattice parameter as a function of Aluminium content is higher than the corresponding bulk lattice parameter of AlxGa1−xSb layers obtained with Vegard's law. These results show that some of the layers are more strained than others. Two peaks are observed in their Raman spectra over this composition range. The assignment of the observed modes to GaSb-like modes is discussed. The studies of the chemical composition of the layers by SIMS exhibit the presence of tellurium, carbon and oxygen like the main residual impurities.