IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS2-ThA

Paper SS2-ThA3
Evolution of Mounds during Ag/Ag(100) Homoepitaxy: Temperature Dependence of Pre-asymptotic Behavior

Thursday, November 1, 2001, 2:40 pm, Room 122

Session: Nucleation & Growth
Presenter: K.J. Caspersen, Iowa State University
Authors: K.J. Caspersen, Iowa State University
A.R. Layson, Iowa State University
C.R. Stoldt, University of California at Berkley
V. Fournee, Iowa State University
P.A. Thiel, Iowa State University
J.W. Evans, Iowa State University
Correspondent: Click to Email
Step edge barriers are known to induce unstable epitaxial growth characterized by "mound" formation, but a detailed understanding of the roughening and coarsening dynamics is lacking. Most theoretical studies aim to elucidate asymptotic behavior for simple models in the regime of (mound) slope selection. We instead perform realistic atomistic modeling of Ag/Ag(100) growth where slope selection is often slow, and the experimentally relevant "pre-asymptotic" behavior is then characterized by slow coarsening and rapid roughening. To describe observed 25ML morphologies from 150-300K ,@footnote 1@ our model includes irreversible island formation (with a 0.40eV barrier for terrace diffusion), distinct step edge barriers for straight and kinked step edges (0.07eV and ~0eV), and a realistic description of periphery diffusion which controls island shapes and coalescence (rapid diffusion along straight steps; 0.41eV barrier for kink rounding). This model then reproduces the key features of mound evolution observed at various temperatures for growth up to 60-100ML, it allows a precise characterization of evolution of the mound distribution (as quantified by a suitable tessellation), and also reveals the crossover to slope selection for thicker films. @FootnoteText@ @footnote 1@K.J. Caspersen et al., Phys. Rev. B 63 (2001) 085401.