In this article, using an in situ micro-structured buffer, we report the growth of high-quality InAs epilayer on GaAs substrate by molecular beam epitaxy. Structural characterization of such InAs epilayer was carried out using cross-sectional transmission electron microscopy (TEM), X-ray diffraction (XRD), and depth-resolved channeling contrast microscopy (CCM). TEM and CCM images clearly show that the dislocations are trapped in the thin buffer layer between the InAs epilayer and the GaAs substrate interface. A narrow XRD peak from the InAs epilayer grown by this technique indicates good crystalline quality. In addition, the XRD peak position and the optical phonon peaks obtained from micro-Raman measurements confirm that the strain has been released in the InAs epilayer. (C) 2004 Elsevier B.V. All rights reserved.