Quantitation of surface electron spectroscopies: problems in correct description of intrinsic lineshape and extrinsic energy loss processes

Abstract

Methods for improved description of lineshapes and energy loss backgrounds in the surface electron spectroscopies. Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS), are discussed. For simple homogeneous non-metallic materials in the near surface region, the energy loss profiles are a small contribution to the total spectral intensity and can be adequately described by simple background functions. For many pure metals or metal alloys, with or without thin adsorbate overlayers, it is necessary to use more realistic models for the energy loss profiles. These can be generated from functions which describe the electron emission event on a microscopic scale, and/or from electrons beams which are scattered from the surface at the kinetic energy of the photoemission or Auger process of interest. Deconvolution schemes (particularly using Fast Fourier Transform approaches) and non-linear least squares fitting routines are compared for preparing the XPS or AES lineshapes for further analysis.