AVS 52nd International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeM

Paper AS-WeM5
Software Package to Determine @epsilon@(k,@omega@) from Analysis of REELS

Wednesday, November 2, 2005, 9:40 am, Room 206

Session: Essential Tools for Surface Analysis
Presenter: S. Tougaard, University of Southern Denmark
Authors: S. Tougaard, University of Southern Denmark
F. Yubero, Inst. de Ciencia de Materiales de Sevilla, Spain
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Engineering of new thin solid films of varying composition are of current high technological interest. Methods to determine the electronic properties of thin films are therefore of increasing importance. The complex dielectric function @epsilon@(k,@omega@) contains valuable information on the electronic structure. The effective single scattering cross section can be determined from analysis of reflected electron energy loss spectra (REELS)@footnote 1@ and a semi-classical dielectric response model for REELS was also developed.@footnote 2,3@ It has been shown how this can be applied to determine @epsilon@(k,@omega@) from analysis of experimental REELS. This provides an intesting technique because REELS is rather simple to apply, it is inexpensive, it is available in many laboratories and above all it can easily be applied to thin films of only a few nano-meters thickness grown on a supporting substrate. The complexity of the formulas has however been a hindrance for widespread use of the technique. To make it generally available, we decided to develop a software package with a user friendly graphical interface and interactive facilities. We hope that this tool will inspire more widespread use of this method to explore the electronic properties of solids and thin films. @epsilon@(k,@omega@) can also be used to make quantitative interpretation of the fundamental mechanisms in photo- and Auger electron spectroscopy and to calculate the inelastic mean free path for electrons in solids and determine the excitations that take place when the electron moves in the surface region or in the vacuum above the surface. The software, which is free of charge for non-commercial use, handles the theory developed in the following papers:. @FootnoteText@ @footnote 1@ S. Tougaard and I. Chorkendorff, Phys. Rev. B23 6570 (1987)@footnote 2@ F. Yubero and S. Tougaard, Phys. Rev B46, p. 2486 (1992)@footnote 3@ F. Yubero, J.M. Sanz, B. Ramskov and S. Tougaard, Phys Rev. B53, 9719 (1996).