Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)

O 27.54: Poster

Dienstag, 24. März 2009, 18:30–21:00, P2

The influence of diffusion anisotropy and strain on Ag nanowire formation on flat and vicinal Si(001) — •Dirk Wall, Simon Sindermann, Michael Horn-von Hoegen, and Frank-Joachim Meyer zu Heringdorf — Address: Department of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) Universität Duisburg-Essen, D-47057 Duisburg, Germany

Photoemission Electron Microscopy (PEEM) and Low Energy Electron Microscopy (LEEM) are used to study the self organized growth of Ag nanowires on flat and vicinal Silicon (001) surfaces. The nanowires form along the two dimer row directions on the flat Si substrate. During growth on substrates with higher vicinalities, between 0^∘ and 4^∘ along the [110] direction, the wires start to form predominantly aligned with the steps. Finally, on a 4^∘ vicinal substrate, all wires are aligned with the steps [1]. This increasing alignment of the nanowires along the [110] direction is attributed to the increase in diffusion anisotropy of Ag adatoms on increasingly vicinal Si substrates [1,2]. For strained islands, calculations predict that the islands will nucleate in a symmetrical shape on the surface until the lattice mismatch forces the islands to become elongated in one direction and shrink in the perpendicular direction [3]. We will show present results as to which of the two mechanisms, strain and/or diffusion anisotropy are affecting wire formation. [1] D. Wall et. al.; J. P.:Cond. Matt. (submitted) [2] D. Wall et. al.; Mater. Res. Soc. Symp. Proc. 1088E; 1088-W05-04(2008) [3] J. Tersoff, R. M. Tromp; Phys. Rev. Lett. 70 (1993) 2782