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 42.21: Poster

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

Nanostructuring of thin V2O3 films on Au(111) by sputtering — •Liz Michaela Rösken, Florian Lovis, Armin Feldhoff, and Ronald Imbihl — Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstr. 3-3a, D-30167 Hannover, Germany

Thin V2O3 films of approximately 1 - 100 ML thickness on Au(111) were prepared by evaporation of vanadium in an O2 atmosphere (p(O2) = 10-7 mbar). The films were characterized by LEED, Auger electron spectroscopy and photoelectron emission microscopy (PEEM). With annealing at T = 350° C epitaxial V2O3 films were found exhibiting (sqrt3 x sqrt3)R30° and (2x2) structures. Only after longer exposure to hydrogen (1-3 h) some reduction of the V2O3 film could be seen as evidenced by an increase of the PEEM brightness corresponding to a work function decrease. Upon sputtering the film displayed some unexpected optical effects: depending on the angle of observation the films appeared red or green. Secondary electron microscopy (SEM) revealed that the sputtering has led to island formation on the surface. The islands exhibit an average diameter of 20 nm and an average separation from each other of 20 nm. As possible mechanisms causing the island formation selective sputtering and the transformation of the 2D layer V-oxide into a 3D layer are discussed.