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Insights into the Electronic Structure of Ceramics Through Quantitative Analysis of Valence Electron Energy-Loss Spectroscopy (VEELS)

Published online by Cambridge University Press:  02 July 2020

Harald Müllejans  and
Roger H. French
Harald Müllejans
Affiliation:
Institute for Advanced Materials, JRC, EC, PO Box 2, NL-1755 ZG, Petten, The Netherlands
Roger H. French
Affiliation:
DuPont Central Research, E356-384 Experimental Station, Wilmington, DE19880, USA
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The electronic structure of ceramics can be extracted quantitatively from the valence electron energy-loss spectroscopy (VEELS) of transitions between the valence and conduction bands. We obtained VEEL spectra of several ceramics (FIG. 1) with a VG HB501 dedicated STEM equipped with Gatan PEELS. Improved data acquisition and new methods of data analysis allowed us to treat the data fully quantitatively. The reliable and accurate removal of the zero loss peak was crucial because intensities at energy losses just above the band gap of the ceramic material have a large influence on the results. An asymmetric Pearson VII function was fitted into the zero loss peak up to an energy loss for which no transitions are expected (an energy smaller than the band gap of the ceramic) and then extrapolated to higher energies. This limits the analysis to non-metallic materials, exhibiting non-zero band gap energies. We are currently developing methods to perform the analysis on metallic materials, using ellipsometric data in the visible and extrapolate the energy-loss function to 0 eV and thereby remove the need for the no transition energy.

Type
A. Howie Symposium: Celebration of Pioneering Electron Microscopy
Information
Microscopy and Microanalysis , Volume 5 , Issue S2: Proceedings: Microscopy & Microanalysis '99, Microscopy Society of America 57th Annual Meeting, Microbeam Analysis Society 33rd Annual Meeting, Portland, Oregon August 1-5, 1999 , August 1999 , pp. 666 - 667
Copyright
Copyright © Microscopy Society of America

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References

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7. This work was partly carried out at the Max-Planck-Institut für Metallforschung, Stuttgart, Germany and partly within the European Commissions’s Research and Development Programme.Google Scholar