Nanostructured Metallic Thin Films: Measurement of Critical Exponents
M. Cattani, L.L. Melo, R.J.C. Farias, M.C. Salvadori
University of Sao Paulo, BR
Keywords: nanostructured metallic films, critical exponents
We have deposited metallic films (Au, Pt) on silicon substrates. The deposition technique was the "Metal Plasma Immersion Ion Implantation and Deposition". Their roughnesses have been measured using a Scanning Tunneling Microscope. From these roughnesses, we determined the scaling critical exponents, a and b, which characterize the dynamics of the film growth process.
The exponents, a and b, were determined following the procedure adopted in previous works.
The relevant growth mechanisms are mainly desorption, nonlinear effects and surface diffusion effects. The competition between the desorption and diffusion terms generates, a characteristic length scale lx. For short length scale (l < lx) we believe that the diffusive term determines the scaling behavior, giving a " 1. For large length scale, that is for l > lx, the desorption and nonlinear terms are expected to be dominant. In these conditions, we expect that the Kardar-Parisi-Zhang (KPZ) would be obeyed. In this case the "KPZ signature" would be obeyed, that is, a + a/b = 2, as evidence for the validity of the KPZ equation. Long range spatial and temporal correlations effects in the noise function h2(x,t) are also being investigated.
NSTI Nanotech 2003 Conference Technical Program Abstract