HIGH-RESOLUTION X-RAY-DIFFRACTION STUDY OF INAS-GAAS SUPERLATTICES GROWN BY MOLECULAR-BEAM EPITAXY AT LOW-TEMPERATURE

InAs-GaAs superlattices grown by molecular-beam epitaxy at low tempera ture are investigated by high-resolution x-ray diffractometry. It is s hown that despite a very high density of point defects due to the pres ence of excess arsenic, the as-grown superlattice has high crystal per fection. An analysis of the changes in the x-ray diffraction curves sh ows that high-temperature annealing, which is accompanied by the forma tion of As clusters and diffusion of indium, produces significant stru ctural transformations in the GaAs matrix and at the interfaces. (C) 1 998 American Institute of Physics.