AVS 52nd International Symposium
    Surface Science Thursday Sessions
       Session SS3-ThM

Paper SS3-ThM1
Temperature Effects on the Nucleation and Growth of Ag Films on 5-fold Surfaces of Icosahedral Al-Pd-Mn Quasicrystal

Thursday, November 3, 2005, 8:20 am, Room 203

Session: Reactivity of Bimetallic Surfaces
Presenter: B. Unal, Iowa State University
Authors: B. Unal, Iowa State University
T.A. Lograsso, The Ames Laboratory
A.R. Ross, The Ames Laboratory
C.J. Jenks, Iowa State University and the Ames Laboratory
J.W. Evans, Iowa State University and the Ames Laboratory
P.A. Thiel, Iowa State University and the Ames Laboratory
Correspondent: Click to Email
Growth of thin films on surfaces of complex intermetallics, such as quasicrystals, can provide new insights into nucleation, growth, and the thermodynamic factors that control film structures. We have used scanning tunneling microscope to study the growth and nucleation of the first few monolayers of Ag on the fivefold surface of an icosahedral Al-Pd-Mn quasicrystal surface at different temperatures. While Ag films grow layer by layer at 127K and 200K, the growth mode switches at about room temperature. Between 300 and 365 K, the Ag segregates in islands that are 4 and 5 monolayers high, on the terraces. When the temperature reaches 420K, islands grow at the step edges rather than on the terraces. This behavior will be discussed in terms of the existence of different types of diffusion barriers on the quasicrystal surface.