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EELS of Niobium and Stoichiometric Niobium-Oxide Phases—Part II: Quantification

Published online by Cambridge University Press:  26 October 2009

David Bach ,
Reinhard Schneider  and
Dagmar Gerthsen
David Bach*
Affiliation:
Laboratorium für Elektronenmikroskopie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
Reinhard Schneider
Affiliation:
Laboratorium für Elektronenmikroskopie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
Dagmar Gerthsen
Affiliation:
Laboratorium für Elektronenmikroskopie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
*
Corresponding author. E-mail: bach@lem.uni-karlsruhe.de
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Abstract

A comprehensive electron energy-loss spectroscopy (EELS) study of niobium (Nb) and stable Nb-oxide phases (NbO, NbO2, Nb2O5) was carried out. Part II of this work is devoted to quantitative EELS by means of experimental k-factors derived from the intensity ratio of the O-K edge and the Nb-M4,5 or Nb-M2,3 edges for all three stable Nb-oxides. The precision and accuracy of the quantification are investigated with respect to the influence of intensity-measurement energy windows, background subtraction, and sample thickness. Integration-window widths allowing optimum accuracy are determined. Owing to background-subtraction errors, the Nb-M4,5 edges rather than Nb-M2,3 are preferred for quantification. Different approaches are applied to improve the precision with regard to thickness-related errors. Thus, a precision up to ±1.5% is achieved by averaging spectra from all three reference oxides to determine a k-factor using Nb-M4,5. Using the experimental k-factor, the determination of atomic concentration ratios CNb/CO in the range of 0.4 (Nb2O5) to 1 (NbO) was found to be possible with an accuracy of 0.6% (relative deviation between measured and nominal composition), whereas ratios of calculated partial ionization cross sections lead to less accurate results.

Keywords

niobium oxideNbONbO2Nb2O5EELSquantificationk-factorprecisionaccuracy
Type
Materials Science Applications
Information
Microscopy and Microanalysis , Volume 15 , Issue 6 , December 2009 , pp. 524 - 538
Copyright
Copyright © Microscopy Society of America 2009

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References

REFERENCES

Ahn, C. & Rez, P. (1985). Inner shell edge profiles in electron energy loss spectroscopy. Ultramicroscopy 17, 105–116.Google Scholar
Auerhammer, J., Rez, P. & Hofer, F. (1989). A comparison of theoretical and experimental L and M cross sections. Ultramicroscopy 30, 365–370.Google Scholar
Bach, D., Schneider, R., Gerthsen, D., Verbeeck, J. & Sigle, W. (2009). EELS of niobium and stoichiometric niobium-oxide phases—Part I: Plasmon and near-edges fine structure. Microsc Microanal 15, 505–523 (this issue).Google Scholar
Bach, D., Störmer, H., Schneider, R., Gerthsen, D. & Verbeeck, J. (2006). EELS investigations of different niobium oxide phases. Microsc Microanal 12, 416–423.CrossRefGoogle ScholarPubMed
Bertoni, G. & Verbeeck, J. (2008). Accuracy and precision in model based EELS quantification. Ultramicroscopy 108, 782–790.CrossRefGoogle ScholarPubMed
Bruley, J., Williams, D.B., Cuomo, J.J. & Pappas, D.P. (1995). Quantitative near-edge structure analysis of diamond-like carbon in the electron microscope using two-window method. J Microsc 180, 22–32.Google Scholar
Brydson, R. (1991). Interpretation of near-edge structure in the electron energy-loss spectrum. EMSA Bull 21, 57–67.Google Scholar
Brydson, R. (2001). Electron Energy Loss Spectroscopy. Oxford, UK: BIOS Scientific Publishers Ltd.Google Scholar
Egerton, R.F. (1978). Formulae for light-element microanalysis by electron energy-loss spectrometry. Ultramicroscopy 3, 243–251.CrossRefGoogle ScholarPubMed
Egerton, R.F. (1979). K-shell ionization cross-sections for use in microanalysis. Ultramicroscopy 4, 169–179.Google Scholar
Egerton, R.F. (1986). Electron Energy-Loss Spectroscopy in the Electron Microscope. New York: Plenum Press.Google Scholar
Fix, T., Ulhaq-Bouillet, C., Colis, S., Dinia, A., Bertoni, G., Verbeeck, J. & Van Tendeloo, G. (2007). Nanoscale analysis of interfaces in a metal/oxide/oxide trilayer obtained by pulsed laser deposition. Appl Phys Lett 91, 023106.CrossRefGoogle Scholar
Gmelin. (1970). Gmelin Handbuch der Anorganischen Chemie, Niob, Teil B1. Weinheim, Germany: Verlag Chemie GmbH.Google Scholar
Hanada, N., Ichikawa, T. & Fujii, H. (2007). Hydrogen absorption kinetics of the catalyzed MgH2 by niobium oxide. J Alloy Compd 446-447, 67–71.CrossRefGoogle Scholar
Heusing, S., Sun, D.L., Otero-Anaya, J. & Aegerter, M.A. (2006). Grey, brown and blue coloring sol-gel electrochromic devices. Thin Solid Films 502, 240–245.Google Scholar
Hofer, F. (1991). Determination of inner-shell cross-sections for EELS-quantification. Microsc Microanal Microstruct 2, 215–230.Google Scholar
Hofer, F. & Golob, P. (1988). Quantification of electron energy-loss spectra with K and L shell ionization cross-sections. Micron Microsc Acta 19, 73–86.CrossRefGoogle Scholar
Hofer, F., Golob, P. & Brunegger, A. (1988). EELS quantification of the elements Sr to W by means of M45 edges. Ultramicroscopy 25, 81–84.Google Scholar
Hofer, F. & Kothleitner, G. (1993). Quantitative microanalysis using electron energy-loss spectroscopy: I. Li and Be in oxides. Microsc Microanal Microstruct 4, 539–560.CrossRefGoogle Scholar
Hofer, F. & Kothleitner, G. (1996). Quantitative microanalysis using electron energy-loss spectroscopy: II. Compounds with heavier elements. Microsc Microanal Microstruct 7, 265–277.CrossRefGoogle Scholar
Hofer, F., Kothleitner, G. & Rez, P. (1996). Ionization cross-sections for the L23-edges of the elements Sr to Mo for quantitative EELS analysis. Ultramicroscopy 63, 239–245.CrossRefGoogle Scholar
Keast, V.J., Scott, A.J., Brydson, R., Williams, D.B. & Bruley, J. (2001). Electron energy-loss near-edge structure—A tool for the investigation of electronic structure on the nanometre scale. J Microsc 203, 135–175.CrossRefGoogle ScholarPubMed
Leapman, R.D., Rez, P. & Mayers, D.F. (1980). K, L, and M shell generalized oscillator strengths and ionization cross sections for fast electron collisions. J Chem Phys 72, 1232–1243.Google Scholar
Malis, T., Cheng, S.C. & Egerton, R.F. (1988). EELS log-ratio technique for specimen-thickness measurement in the TEM. J Electron Micr Tech 8, 193–200.CrossRefGoogle ScholarPubMed
Malis, T. & Titchmarsh, J.M. (1986). “k-kactor” approach to EELS analysis. In Electron Microscopy and Analysis 1985, pp. 181–182. Bristol, UK: Institute of Physics.Google Scholar
Olszta, M.J. & Dickey, E.C. (2008). Interface stoichiometry and structure in anodic niobium pentoxide. Microsc Microanal 14, 451–458.Google Scholar
Olszta, M.J., Wang, J. & Dickey, E.C. (2006). Stoichiometry and valence measurements of niobium oxides using electron energy-loss spectroscopy. J Microsc 224, 233–241.Google Scholar
Qiu, Y., Smyth, D. & Kimmel, J. (2002). The stabilization of niobium-based solid electrolyte capacitors. Active and Passive Electr Comp 25, 201–209.CrossRefGoogle Scholar
Rez, P. (1982). Cross-sections for energy loss spectrometry. Ultramicroscopy 9, 283–288.CrossRefGoogle Scholar
Rho, S., Jahng, D., Lim, J.H., Choi, J., Chang, J.H., Lee, S.C. & Kim, K.J. (2008). Electrochemical DNA biosensors based on thin gold films sputtered on capacitive nanoporous niobium oxide. Biosens Bioelectron 23, 852–856.Google Scholar
Sasaki, K., Zhang, L. & Adzic, R.R. (2008). Niobium oxide supported platinum ultra-low amount electrocatalysts for oxygen reduction. Phys Chem Chem Phys 10, 159–167.CrossRefGoogle ScholarPubMed