Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth

O 59.3: Vortrag

Mittwoch, 18. März 2015, 15:30–15:45, MA 042

Growth of cuprous oxide on Au(111) and Mo(001) - Role of the support — •Hanna Fedderwitz, Boris Groß, Hendrik Sträter, and Niklas Nilius — Carl-von-Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9 - 11, 26129 Oldenburg

Physical vapor deposition of Cu in an oxygen ambience is used to prepare Cu₂O films on two single crystalline supports of different reactivity and lattice symmetry. While on Au(111), the oxide grows in a layer by layer fashion and develops atomically flat films, formation of nanoparticles is observed on a Mo(001) surface. The size and shape of the crystallites can be controlled by varying the temperature and O₂ partial pressure during oxide growth. Insight into the atomic configuration of the Cu₂O facets is obtained from low-temperature STM measurements. Whereas Au-supported films expose the ideal (111) termination of cuprous oxide, modified only be a network of dislocation lines, a variety of low-index planes is discernable for deposits on the Mo support. The underlying growth mechanism is analyzed with the Wulff theory for nanoparticles in thermodynamic equilibrium. We discuss consequences of the different growth schemes on the two supports for possible applications of our cuprous-oxide samples in photo-catalysis and photovoltaics.