Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Surfaces and Films: Forces, Structure and Manipulation

O 36.10: Vortrag

Dienstag, 26. Februar 2008, 16:30–16:45, MA 041

Photoemission experiments using soft x-ray standing waves — •Sven Döring^{1, 2}, Daniel Weier^{1, 2}, Ulf Berges^{1, 2}, Charles S. Fadley^{3, 4, 5}, and Carsten Westphal^{1, 2} — ¹DELTA, TU Dortmund, Maria-Goeppert-Mayer-Str. 2, 44221 Dortmund, Germany — ²Experimentelle Physik 1, TU Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund, Germany — ³Materials and Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA — ⁴University of California, Davis, CA 95616, USA — ⁵Forschungszentrum Jülich, IFF-9, 52425 Jülich, Germany

A high depth resolution can be obtained by creating a soft x-ray standing wave field on the sample surface and performing photoemission experiments in this field. A high reflectivity is necessary for a sufficient standing wave modulation. Multilayer samples are used which provide a strong first order Bragg reflection. The standing wave field can be moved through the sample surface by a sample rotation around the Bragg angle. The shape and modulation of these rocking curves contain information about the sample. First measurements on various samples were performed at the TU Dortmund’s synchrotron light source DELTA and at higher energies at BESSY II in Berlin. Results from different samples will be presented in the talk: rocking curves from bare multilayers will be shown as well as a first test measurement of a thin layer of MgO on a wedge of Fe on top of a multilayer. The data show depth profiles obtained of the internal interface. Different chemical states of the same element can be identified by their chemical shift in the XPS spectrum and allocated to certain layers.