Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 89: Metal Substrates: Epitaxy and Growth

O 89.4: Vortrag

Freitag, 29. Februar 2008, 10:15–10:30, MA 041

Ripple growth and - orientation during grazing incidence deposition of Cu/Cu(001) — •Herbert Wormeester, Frits Rabbering, Georgiana Stoian, Raoul van Gastel, and Bene Poelsema — Solid State Physics, MESA+ Institute for Nanotechnology, University of Twente, The Netherlands

We have studied the consequences of oblique incidence deposition for the morphology of the growth-front for a "prototypical" system Cu/Cu(001). Previous electron diffraction measurements showed that deposition at grazing incidence leads to the evolution of ripples, oriented perpendicular to the plane of incidence of the atom beam. New experimental results with high resolution low energy electron diffraction and STM will be presented. The ripple formation has also been studied with kMC simulations, which support and predicted experimentally observed changes in ripple orientation at later stages in growth. The relevant activation barriers for intra- and interlayer diffusion processes in these simulations have been tuned to describe quantitatively(!) experimentally observed morphologies in a wide range of temperatures (150-300 K) and coverages (up to 40 ML). A change in ripple orientation from perpendicular to parallel to the plane of incidence has been detected around a coverage of 40 ML at a temperature of 250K and a polar deposition angle of 80^∘. At 230K and at more grazing incidence this orientation transition has been found to occur at a much earlier stages in growth. This change in ripple orientation is related to the Super Poisson roughening of the growth front.