AVS 49th International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoA

Paper AS-MoA7
Correcting for Detector-Induced Non Linearity in Photoelectron Spectroscopy Counting Systems

Monday, November 4, 2002, 4:00 pm, Room C-106

Session: Quantification & Accuracy in Surface Analysis
Presenter: C.S. Fadley, University of California at Davis
Authors: C.S. Fadley, University of California at Davis
N. Mannella, University of California at Davis
S. Marchesini, University of California at Davis
A. Kay, Intel Corporation
S.-H. Yang, IBM Almaden Research Center
S. Mun, Intel Corporation
M.A. van Hove, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
The photoelectron intensity levels reached in exciting surfaces with both laboratory sources and third-generation synchrotron radiation can in many cases exceed the linear response range of the final detection system involved.@footnote1@ For example, the quantitative analysis of complex oxides via core-level intensities has been found to be strongly influenced by this non-linearity,@footnote2@ as have angle-resolved valence spectra@footnote3@ and magnetic dichroism measurements on magnetic systems.@footnote2@ Experiments involving resonant photoemission, in which the photon energy is scanned through an absorption edge, are also strongly affected.@footnote4@ In this paper, we demonstrate two quantitatively accurate procedures to correct for such non-linearity effects. The first method directly yields the detector efficiency by measuring a flat-background reference intensity as a function of incident x-ray flux, while the second method determines the detector response from an analysis of broad-scan survey spectra at different incident x-ray fluxes. Although we will use one spectrometer system (the Scienta ES200) as an example, the methodologies discussed here should be useful for many other cases. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences Division, under Contract No. DE-AC03-76SF00098. @FootnoteText@ @footnote1@ M.P. Seah, M. Tosa, Surf. Interface. Anal. 18 (1992) 240; (b) M.P. Seah, I.S. Gilmore, S.J. Spencer, J. Electron Spectrosc. 104 (1999) 73-89. @footnote2@ P. Wernet, N. Mannella et al., to be published. @footnote3@ D. Dessau and Y. Chuang, private communication. @footnote4@ A. Kay, Ph.D. Thesis, University of California Davis, 1998; A.W. Kay et al., Physical Review B 63, 115119,U214-U222 (2001) and references therein.