Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)
O 27.93: Poster
Dienstag, 24. März 2009, 18:30–21:00, P2
High resolution positron annihilation induced Auger spectroscopy on copper — •Jakob Mayer1, Klaus Schreckenbach1,2, and Christoph Hugenschmidt1,2 — 1Technische Universität München, Physikdepartment E21, James- Franck-Str., 85748 Garching — 2ZWE FRM II, Lichtenbergstr.1, 85747 Garching
The high intensity positron source NEPOMUC at the FRM-II in Munich with a stable remoderated positron beam of >107 positrons/s at 20 eV enabled measurement times of 10 hours for one PAES (Positron annihilation induces Auger Electron Spectroscopy) spectrum [1]. Since the intrinsic advantages of PAES over EAES are known and have been shown (e.g. [2]), the reduction of the long measurement times is the main challenge for this non destructive technique for surface studies. For this reason, a new hemispherical electron energy analyzer was installed at the PAES facility of NEPOMUC. Compared to the former analyzer (opening angle ±3∘) it has a much higher solid angle which allows the detection of electrons which are emitted up to an angle of ±13∘ with respect to the lens system of the analyzer. In addition, the freely selectable pass energy (0-600 eV) guarantees a high transmission. Though a high energy resolution is achievable with the big mean radius of the analyzer (150 mm) and variable slits. The new setup and first spectra obtained for polycrystalline copper surfaces (15 min measurement time) will be presented. [1] C. Hugenschmidt, J. Mayer and K. Schreckenbach, Surf. Sci. 601 (2459-2466) 2007 [2] K. O. Jensen and A. Weiss, Phys Rev. B 41 (3928-3936) 1990