AVS 53rd International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeA

Paper SS1-WeA6
Exploring Complex "Wedding-Cake" Film Morphologies: Ag/Ag(111) Epitaxial Growth

Wednesday, November 15, 2006, 3:40 pm, Room 2002

Session: Growth Processes on Metal and Semiconductor Surfaces
Presenter: J.W. Evans, Iowa State University
Authors: M. Li, Iowa State University
P.-W. Chung, Iowa State University
E. Cox, Iowa State University
C.J. Jenks, Iowa State University
P.A. Thiel, Iowa State University
J.W. Evans, Iowa State University
Correspondent: Click to Email
Ag/Ag(111) homoepitaxy constitutes a prototype for rough growth and the formation of wedding-cake morphologies due to the presence of a large Ehrlich-Schwoebel (ES) step-edge barrier inhibiting downward transport. However, systematic analysis of the temperature-dependence of these morphologies is lacking, and dispute persists regarding details of the ES barrier. Our study combines comprehensive VTSTM experiments and realistic atomistic modeling and kinetic Monte Carlo simulation of growth (neither of which was available in previous studies) in the regime of 120-200 K . We thereby selectively probe those features of the rich far-from-equilibrium film morphologies which provide the most insight into the atomistic diffusion processes and barriers controlling growth. Submonolayer island growth shapes around 180K, where the fractal growth instability is quenched but full shape equilibration is not yet achieved, already provide evidence of a non-uniform ES barrier. Detailed analysis of multilayer growth morphologies focusing on top-layer island sizes at the wedding-cake peaks provides the most sensitive assessment of the magnitude of the ES barrier. However, consistent analysis requires accounting for the effect of a transition from irreversible to reversible island formation which inhibits nucleation of top-layer islands.