The n-GaAs layer was successfully grown on (1 0 0) p-type silicon (p-Si) substrate by molecular beam epitaxy (MBE) using rough surface buffer layer (RSi) to reduce the tensile stress in GaAs layer grown on Si substrate. We have reviewed the initial stage and the recombination of GaAs epitaxial layer grown on rugged silicon substrate (RSi). Two dimensional reconstructions were observed for 2 mu m GaAs layer by reflection high-energy electron diffraction (RHEED). High resolution X-ray diffractometer (HRXRD) has been achieved, showing the better relaxation and high quality of n-GaAs layer deposited on p-RSi substrate. The effects of rapid thermal annealing (RTA) on crystal structure of GaAs on Si were studied by analyzing the linewidth of the rocking curve related to the samples. Photocurrent measurements indicate potential application of this structure for photovoltaics. (C) 2011 Elsevier B.V. All rights reserved.