X-ray diffractometric determination of the degree of long-range order in epitaxial InxGa1-xP layers

An x-ray diffractometric study of the degree of the long-range order in epitaxial InxGa1-xP (x=0.44-0.54) solid solutions has been performed. The epitaxial solid solutions were obtained by MOS-hydride epitaxy on the (001)GaAs substrates with a 3 deg. deviation from the (001) plane with respect to the (1-bar10) plane under atmospheric pressure and T=650 deg. C. The intensities of the strongest superstructural 1-bar/2 1/2 1/2 and structural 3-bar33 reflections from the epitaxial layers were measured. The degree of the long-range order was determined from the intensity ratio of these reflections. The maximum degree of the long-range order η=0.41 was observed in the layers of the composition close to x=0.5. At the ends of this composition range the degree of the long-range order reduced to η=0.13