High-resolution x-ray diffraction study of In0.25Ga0.75Sb/InAs superlattice

An In0.25Ga0.75Sb/InAs strained-layer superlattice, grown by molecular-beam epitaxy (MBE) on a GaSb[001] substrate, has been characterized by four-circle x-ray diffractometry. This system, proposed by Maliot and Smith for ir detection application, is challenging because of the two group V species and the likelihood of cross-incorporation of the different elements during growth, leading possibly to interdiffusion and thus, to a more diffuse interface. High-resolution x-ray diffraction (XRD) profiles were obtained about several reciprocal lattice points in order to extract a reliable set of structural parameters. The profiles were then successfully modeled by computer simulation. The presence of many sharp higher-order satellite reflections in the XRD profiles is a measure of the high quality of the superlattices. The normal and lateral structural coherence was also measured and will be discussed.