Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.78: Poster

Montag, 26. März 2007, 17:30–20:30, Poster C

Au induced faceting of Si (112) surfaces and their relevance for vapour-liquid-solid epitaxy — •Christian Wiethoff, Frank Meyer zu Heringdorf, and Michael Horn-von Hoegen — Universität Duisburg-Essen

Silicon nanowires formed during vapour-liquid-solid (VLS) epitaxy, with Au as a catalyst [1] show sidewalls with [112]-orientations. These sidewalls are faceted and it was suggested that Au is the driving force for the faceting [2]. In order to investigate the influence of the catalyst in more detail, we studied Au induced faceting of [112] surfaces at 750°C with spot-profile-analysing-LEED (SPALEED). After quenching to room temperature the structure and step morphology was determined by reciprocal space mapping [3]. After some different phases of faceting a hill and valley structure with giant facets of [111] and [113] orientation form. They reach height modulations of more than 20nm at a periodic length of about 200nm. We suggest that the facets found on the nanowires consist of these orientations. With further Au adsorption, the [113] facets level off and the surface reaches a stable and reasonably smooth faceting configuration.

[1] J. B. Hannon, S. Kodambaka, F. M. Ross and R.M. Tromp, Nature 440, 04574 (2006)

[2] F. M. Ross, J. Tersoff and M. C. Reuter, Phys. Rev. Lett. 95, 146104 (2005)

[3] Frank-J. Meyer zu Heringdorf and Michael Horn-von Hoegen, Rev. Sci. Instrum. 76, 085102, (2005)