Comparison of source functions obtained by using QUASES and partial intensity analysis for inelastic background correction: KLL Auger spectra of 3d transition elements Cu and Ni+

L. Kvr, S. Tougaard, W. S M Werner, I. Cserny

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5 Citations (Scopus)

Abstract

Correction of photoelectron and Auger spectra excited from solids for the effect of electron scattering is a key problem in quantitative surface analytical applications of XPS and AES. Based on analysis of the spectral shape of the background caused by scattering of the signal electrons, powerful methods have been developed recently and applied successfully for obtaining the 'source functions' (i.e. the background-corrected spectra) as well as the in-depth concentration profile from the measured spectra. The QUASES analysis has been proposed as a general tool for quantification in XPS, probing depths up to ∼10 inelastic electron mean free paths (λ) using Tougaard's 'universal' cross-section for inelastic scattering and the λ(E) values recommended by Powell and Jablonski. Effects of elastic scattering and surface excitations are neglected with this approach and intrinsic excitations are considered a part of the source function. In the partial intensity approach, the observed spectrum can be decomposed into its constituent parts, i.e. the source function as well as contributions due to intrinsic bulk losses and surface extrinsic losses. This is achieved for an arbitrary emission mechanism. In particular, elastic scattering and different scattering mechanisms at different depths can be accounted for simply and consistently. Both methods have been applied for background correction of KLL Auger spectra of the 3d transition metals Cu and Ni excited by photons from metallic thin films vacuum-evaporated onto Si substrates. The respective source functions obtained are very similar, especially in the case of thinner films, indicating that elastic scattering and surface effects play only a minor role in influencing the spectral shape at these high energies. A detailed analysis of the differences is given, focusing on the contributions from intrinsic excitations.

Original languageEnglish
Pages (from-to)681-686
Number of pages6
JournalSurface and Interface Analysis
Volume33
Issue number8
DOIs
Publication statusPublished - Aug 2002

Fingerprint

Transition Elements
Electron transitions
Elastic scattering
transition metals
elastic scattering
X ray photoelectron spectroscopy
Scattering
Thin films
Metallic films
Inelastic scattering
Electron scattering
Electrons
excitation
Photoelectrons
Transition metals
thin films
scattering
Photons
mean free path
Vacuum

Keywords

  • AES
  • Copper
  • Inelastic background
  • Nickel
  • Partial intensity analysis
  • QUASES

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

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title = "Comparison of source functions obtained by using QUASES and partial intensity analysis for inelastic background correction: KLL Auger spectra of 3d transition elements Cu and Ni+",
abstract = "Correction of photoelectron and Auger spectra excited from solids for the effect of electron scattering is a key problem in quantitative surface analytical applications of XPS and AES. Based on analysis of the spectral shape of the background caused by scattering of the signal electrons, powerful methods have been developed recently and applied successfully for obtaining the 'source functions' (i.e. the background-corrected spectra) as well as the in-depth concentration profile from the measured spectra. The QUASES analysis has been proposed as a general tool for quantification in XPS, probing depths up to ∼10 inelastic electron mean free paths (λ) using Tougaard's 'universal' cross-section for inelastic scattering and the λ(E) values recommended by Powell and Jablonski. Effects of elastic scattering and surface excitations are neglected with this approach and intrinsic excitations are considered a part of the source function. In the partial intensity approach, the observed spectrum can be decomposed into its constituent parts, i.e. the source function as well as contributions due to intrinsic bulk losses and surface extrinsic losses. This is achieved for an arbitrary emission mechanism. In particular, elastic scattering and different scattering mechanisms at different depths can be accounted for simply and consistently. Both methods have been applied for background correction of KLL Auger spectra of the 3d transition metals Cu and Ni excited by photons from metallic thin films vacuum-evaporated onto Si substrates. The respective source functions obtained are very similar, especially in the case of thinner films, indicating that elastic scattering and surface effects play only a minor role in influencing the spectral shape at these high energies. A detailed analysis of the differences is given, focusing on the contributions from intrinsic excitations.",
keywords = "AES, Copper, Inelastic background, Nickel, Partial intensity analysis, QUASES",
author = "L. Kvr and S. Tougaard and Werner, {W. S M} and I. Cserny",
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T1 - Comparison of source functions obtained by using QUASES and partial intensity analysis for inelastic background correction

T2 - KLL Auger spectra of 3d transition elements Cu and Ni+

AU - Kvr, L.

AU - Tougaard, S.

AU - Werner, W. S M

AU - Cserny, I.

PY - 2002/8

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N2 - Correction of photoelectron and Auger spectra excited from solids for the effect of electron scattering is a key problem in quantitative surface analytical applications of XPS and AES. Based on analysis of the spectral shape of the background caused by scattering of the signal electrons, powerful methods have been developed recently and applied successfully for obtaining the 'source functions' (i.e. the background-corrected spectra) as well as the in-depth concentration profile from the measured spectra. The QUASES analysis has been proposed as a general tool for quantification in XPS, probing depths up to ∼10 inelastic electron mean free paths (λ) using Tougaard's 'universal' cross-section for inelastic scattering and the λ(E) values recommended by Powell and Jablonski. Effects of elastic scattering and surface excitations are neglected with this approach and intrinsic excitations are considered a part of the source function. In the partial intensity approach, the observed spectrum can be decomposed into its constituent parts, i.e. the source function as well as contributions due to intrinsic bulk losses and surface extrinsic losses. This is achieved for an arbitrary emission mechanism. In particular, elastic scattering and different scattering mechanisms at different depths can be accounted for simply and consistently. Both methods have been applied for background correction of KLL Auger spectra of the 3d transition metals Cu and Ni excited by photons from metallic thin films vacuum-evaporated onto Si substrates. The respective source functions obtained are very similar, especially in the case of thinner films, indicating that elastic scattering and surface effects play only a minor role in influencing the spectral shape at these high energies. A detailed analysis of the differences is given, focusing on the contributions from intrinsic excitations.

AB - Correction of photoelectron and Auger spectra excited from solids for the effect of electron scattering is a key problem in quantitative surface analytical applications of XPS and AES. Based on analysis of the spectral shape of the background caused by scattering of the signal electrons, powerful methods have been developed recently and applied successfully for obtaining the 'source functions' (i.e. the background-corrected spectra) as well as the in-depth concentration profile from the measured spectra. The QUASES analysis has been proposed as a general tool for quantification in XPS, probing depths up to ∼10 inelastic electron mean free paths (λ) using Tougaard's 'universal' cross-section for inelastic scattering and the λ(E) values recommended by Powell and Jablonski. Effects of elastic scattering and surface excitations are neglected with this approach and intrinsic excitations are considered a part of the source function. In the partial intensity approach, the observed spectrum can be decomposed into its constituent parts, i.e. the source function as well as contributions due to intrinsic bulk losses and surface extrinsic losses. This is achieved for an arbitrary emission mechanism. In particular, elastic scattering and different scattering mechanisms at different depths can be accounted for simply and consistently. Both methods have been applied for background correction of KLL Auger spectra of the 3d transition metals Cu and Ni excited by photons from metallic thin films vacuum-evaporated onto Si substrates. The respective source functions obtained are very similar, especially in the case of thinner films, indicating that elastic scattering and surface effects play only a minor role in influencing the spectral shape at these high energies. A detailed analysis of the differences is given, focusing on the contributions from intrinsic excitations.

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