High resolution X-ray diffraction (HRXRD) and far-infrared reflectivity techniques were applied to characterize AlxGa1-xSb alloys. Layers of AlxGa1-xSb grown by the liquid phase epitaxy technique and deposited on GaSb (100) substrates were obtained in the temperature range of 250 to 450 degrees C. From the HRXRD measurements it can be inferred that the films have good structural characteristics, this is because the lattice mismatch values were no bigger than 0.02% and from the rocking curves the Al concentration was ranged from 0.04 to 0.058. The presence of the ternary alloy in the films was confirmed by reflectivity. A change of the conductivity type in the film was observed for films grown at temperatures lower than 350 degrees C. (c) 2005 Elsevier B.V. All rights reserved.