Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 70: Methods: Atomic and Electronic Structure III
O 70.1: Vortrag
Freitag, 30. März 2007, 10:15–10:30, H42
Positron annihilation induced Auger electron spectroscopy (PAES) of thin metal layers on Cu and Si — •Jakob Mayer1, Christoph Hugenschmidt1,2, Philip Pikart1, and Klaus Schreckenbach1,2 — 1Technische Universität München, Physikdepartment E21, James-Franck-Str., 85748 Garching — 2Technische Universität München, ZWE FRM-II, Lichtenbergstr. 1, 85748 Garching
The high intense positron source NEPOMUC at the FRM-II in Munich provides an intensity of ≥ 107 moderated (15 eV) positrons/s. This facility enables measurement times for positron annihilation induced Auger electron spectroscopy (PAES) of a few hours/spectrum. In contrast to the usual 22Na based lab beams with a measurement time of several days, at NEPOMUC a spectrum can be obtained after only three hours. Compared with conventional EAES, PAES has a much higher surface sensitivity and due to the low positron energy even weakly bound atoms/molecules at the surfaces are not destroyed by the incident positron beam. Another advantage of PAES is the low background in the energy region of the Auger peaks.
The primarily high electron background due to surrounding experiments in the experimental hall of the FRM-II has been eliminated and hence background free experiments have become possible. Measurements of single crystalline silicon, polycrystalline copper and Cu coated Si are presented and compared with EAES respectively. The results reveal the advantages and the surface sensitivity of PAES.