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O: Fachverband Oberflächenphysik
O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures
O 37.69: Poster
Dienstag, 1. April 2014, 18:30–22:00, P2
Two-Photon Photoemission from magnesium oxide — •Rebecca Pöschel, Andrej Classen, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Staudtstr. 7, D-91058 Erlangen
We prepared MgO by evaporating magnesium on a well-defined Ag(100) single-crystal surface kept at 473 K in 10−7 mbar oxygen. Thin films of different thicknesses between 0.25 and 10 monolayers (ML) were deposited on the crystal. The samples were studied by two-photon photoelectron spectroscopy (2PPE) (1.55 eV and 4.65 eV) and by vacuum ultra-violet (VUV) photoelectron spectroscopy (21.2 eV). The work function decreases with increasing thickness and reaches a value of 3.14 eV for 10 ML. The image potential states of Ag(100) are seen for MgO coverages up to 1 monolayer. Between 1 and 2.5 ML the 2PPE spectra are rather structureless and make MgO an ideal substrate for the study of unoccupied electronic states of adsorbed molecules.