Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.15: Poster

Tuesday, March 23, 2010, 18:30–21:00, Poster B1

Formation of the Si(111)-2×1 reconstruction — Thomas K. A. Spaeth, Martin Wenderoth, •Karolin Löser, and Rainer G. Ulbrich — IV. Physikalisches Institut, Georg-August Universität Göttingen, Germany

The Si(111)-2×1 reconstructed surface is obtained by cleavage at RT in the UHV. It consists of π-bonded chains which can run in the three equivalent lattice directions [011], [110] and [101]. Different kinds of anti-phase-boundaries (APB) are theoretically possible between domains of reconstructed π-bonded chains: (i) APB separating domains of different chain orientations or (ii) APB resulting from a ‘stacking fault’ of the 2×1 reconstruction along or across the chains, i.e. the displacement can be either between two chains or within each chain. We have studied cleaved Si(111)-2×1 samples with high-resolution STM in UHV and observed APBs separating domains with different chain orientations as well as APBs with the displacement within each chain of the same direction. A displacement between two parallel chains was not found. In sample areas containing surface steps, APBs typically run parallel to the steps, within a few nm distance. We also find a clear preference for the [110] and the [101] direction while chains running parallel to the nominal propagation of the cleavage in [011] direction occur only in very few and small domains, and often linked with steps nearby. Our results provide strong indication that cleavage related surface steps control the formation of the 2×1 reconstruction domains on the Si(111) surface. We acknowledge financial support by the DFG via project WE 1889/3.