Münster 1999 – scientific programme

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O: Oberflächenphysik

O 10: Epitaxie und Wachstum (I)

O 10.6: Talk

Monday, March 22, 1999, 17:30–17:45, S2

Diffusion mechanisms and the nature of Si ad-dimers on Ge(001) — •E. Zoethout, H.J.W. Zandvliet, W. Wulfhekel, G. Rosenfeld, and B. Poelsema — Department of Applied Physics and Centre of Materials Research, University of Twente, PO Box 217, Enschede, The Netherlands

The thermal motion of Si ad-dimers on Ge(001) has been studied with Scanning Tunneling Microscopy. At room temperature the Si ad-dimers residing on top of substrate dimer rows perform a 1-dimensional random walk along the substrate dimer rows. The activation barrier for the diffusion process is estimated to be 0.83 eV. Although the preferential diffusion direction is along the substrate dimer rows also diffusion across rows has been observed. The latter diffusion process consists of two separate events: a jump of a Si ad-dimer from an on top position to a position in the trough between the substrate dimer rows and a hop from a trough position to an on top position.