Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.2: Poster

Mittwoch, 25. März 2009, 17:45–20:30, P2

Terephthalic acid (TPA) on Si(111)-α and β-(( 3)^1/×( 3)^1/)-Bi surfaces — •Takayuki Suzuki¹, Theresa Lutz¹, Giovanni Costantini^1,2, and Klaus Kern^1,3 — ¹Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany — ²Department of Chemistry, University of Warwick, Coventry, CV4 7AL, United Kingdom — ³Institute de Physiques des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

We have carried out scanning tunneling microscopy (STM) experiments of terephthalic acid (TPA) adsorption on Si(111)-α and β-(( 3)^1/×( 3)^1/)-Bi surfaces in order to study supramolecular self-assembly on passivated semiconductor surfaces. Both Si(111)-α and β-(( 3)^1/×( 3)^1/)-Bi are passivated semiconductor surfaces without highly reactive Si dangling bonds, and have Bi coverages of 1/3 and 1 monolayer, respectively. The TPA molecules adsorb randomly on α-(( 3)^1/×( 3)^1/)-Bi and do not form any ordered supramolecular layer. On the other hand, they form ordered supramolecular layers on β-(( 3)^1/×( 3)^1/)-Bi with at least four different types of coexisting structures. This completely different supramolecular self-assembly behavior on the α and β-(( 3)^1/×( 3)^1/)-Bi surfaces is quite striking since the two substrates are composed by the same atomic species and are characterized by the same unit cell. The different behavior is related to the differences in the electronic structure of these surfaces. Similar to the Si dangling bond states on Si(111)-7×7, localized surface states exist on Bi adatoms on α-(( 3)^1/×( 3)^1/)-Bi, but not on Bi trimers on β-(( 3)^1/×( 3)^1/)-Bi.