AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS3-TuA

Paper SS3-TuA8
Enhanced Interlayer Mass Transport and Dynamics of Film Smoothening on a Symmetry-broken Ag(111) Surface

Tuesday, October 26, 1999, 4:20 pm, Room 607

Session: Diffusion on Surfaces
Presenter: H. Yu, University of Texas, Austin
Authors: H. Yu, University of Texas, Austin
C.-S. Jiang, University of Texas, Austin
Ph. Ebert, Forschungszentrum J@um u@lich, Germany
X.-D. Wang, University of Texas, Austin
C.K. Shih, University of Texas, Austin
Correspondent: Click to Email
We have studied the dynamics of the film flattening process at room temperature and higher annealing temperatures of Ag films deposited at low temperature on GaAs(110) surfaces. We will present a scanning tunneling microscopy movie, which shows the evolution of the film morphology over 13 hours at room temperature. The initial surface contains a distribution of surface heights up to five monolayers. The vacancy islands at the lowest layer and the islands at the top layer both decay very rapidly with the same decay constants. The remaining islands (of a surface with three monolayers exposed) decay with a much slower rate and we observed a freeze of decay after about 7 hours. Consecutive annealing up to 400 K induces a further decay of the roughness, such that finally nearly only two layers are exposed. The island size increased during room temperature and consecutive annealing steps considerably and the steps align preferentially along the high symmetry directions of the twofold superstructure present on the Ag surface. These results demonstrate the existence of a considerably enhanced interlayer mass transport and a different symmetry behavior compared to those observed for Ag homoepitaxy on Ag(111) surfaces. The enhanced interlayer mass transfer is interpreted in terms of a very low Ehrlich-Schwoebel barrier.