Xu, H. Y.Guo, Y. N.Wang, Y.Zou, J.Kang, J. H.Gao, Q.Jagadish, C.Tan, Hark Hoe2015-10-232015-10-230021-8979http://hdl.handle.net/1885/16060GaAsthin filmsgrown on Si (100) and (111) substrates by metal-organic chemical vapor deposition were investigated by electron microscopy. It was found that the growth rate of the GaAsepitaxial layers on Si (100) was faster than that on Si (111) due to a lower Si (111) surface energy. The morphologies and internal crystal structure quality of GaAsfilmsgrown on Si (111) were better than those grown on Si (100). It was also found that postannealing at high temperature can improve the morphology of the epitaxial layer surface and reduce lattice defects in the thin films.The Australian Research Council is acknowledged for its financial support.http://www.sherpa.ac.uk/romeo/issn/0021-8979..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 23/10/15). Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics and may be found at https://doi.org/10.1063/1.3248372Keywords: GaAs; GaAs films; GaAs on Si; GaAs thin films; High temperature; Lattice defects; Metalorganic chemical vapor deposition; Post annealing; Si (1 1 1); Si(1 0 0); Substrate orientation; Surface energies; Crystal structure; Deposition; Epitaxial films; Epita2009-10-2310.1063/1.32483722016-02-24