Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Focus Session: Frontiers in Reducible Oxide Surface Science II

O 18.3: Vortrag

Montag, 12. März 2018, 16:00–16:15, HE 101

MnO(001) thin films on Au(111) — •Christoph Möller and Niklas Nilius — Institute of Physics, Carl von Ossietzky University, 26111 Oldenburg, Germany

A variety of oxidation states and a high reactivity make manganese oxide a promising material for applications in heterogeneous catalysis. Using STM and XPS, we have probed the structural and electronic properties of ultrathin MnO films deposited on the Au(111) surface. At low coverage, the oxide crystallizes into regular islands with up to 50 nm diameter. Their surface exposes either a 2x2 reconstruction or various stripe phases, depending on the island height. The MnO band gap was determined to 2.8 eV, while the first field-emission resonance occurs at 3 eV, indicating a drastic decrease of the gold work function upon MnO deposition. With increasing thickness, the oxide grows into a polycrystalline, non-conductive film, whose stoichiometry increasingly deviates from MnO.