Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 71: Metal substrates: Epitaxy and growth

O 71.9: Vortrag

Donnerstag, 25. März 2010, 17:00–17:15, H31

Temporal evolution of Pb-islands on Ni(111) — •Tjeerd R.J. Bollmann, Raoul van Gastel, and Bene Poelsema — MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands

Low Energy Electron Microscopy (LEEM) allows real-time imaging of epitaxial growth of metals on metal substrates. We have used LEEM in combination with micro Low Energy Electron Diffraction to study the structure, size and height evolution of Pb islands on top of a Pb wetting layer on a Ni(111) surface, as well as the diffusion of islands across steps during epitaxial growth at elevated temperatures. Pb islands diffusing across nickel steps show remarkable self-organization in that they can half their surface area by doubling their layer in height. Concerted rapid coarsening of (larger) Pb islands within seconds is also observed. In both cases mass transport of Pb leads to new island equilibrium shapes with increased uniform (integer) heights. We present a systematic LEEM investigation of the effects that play a role in the area versus height evolution of Pb islands at elevated temperatures. The results are discussed in view of quantum size effect driven growth where specific heights are particularly stable.