Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Metal Substrates I

O 59.7: Vortrag

Mittwoch, 2. April 2014, 17:30–17:45, WIL A317

Temperature Dependent Electronic Structure of the CuN c(2x2) on Cu(100) Overlayer — •Ivan Baev, Henrike Hümpel, Michael Martins, and Wilfried Wurth — Institut für Experimentalphysik, Universität Hamburg

CuN c(2x2) on Cu(100) is a promising surface insulator to study nanoparticles. If the size of deposited particles is small, then the coupling of the particles to the surface is often stronger than the size dependent effects within the particles itself. In such a case CuN can be used to decouple the particles from the metallic substrate without the disadvantages of a bulk insulator. Former characterizations of the CuN layer were focused on LEED and STM techniques. Only a few studies involving core level photoemission exist.

We have performed annealing temperature dependent X-Ray photoemission spectroscopy with an energy resolution sufficient to separate various contributions to the resulting core level photoemission lines. Complimentary, we also performed LEED and STM investigations in a so far not investigated temperature and nitrogen-dose range.

The results show that an interpretation of the CuN system involving LEED and STM experiments only, is dangerous. Our stoichiometric evaluation together with core level binding energy shifts shows, that a full monolayer coverage of CuN is formed under rather different conditions than it is generally perceived in the literature. Also, we can show that the usual preparation technique involving low energy sputtering of nitrogen onto Cu(100) is probably not suitable to achieve a large homogeneous CuN coverage density.