Veels Spectroscopy

R. H. French, H. Müllejans, D. J. Jones, G. Duscher, R. M. Cannon, M. Rühle, “Dispersion Forces and Hamaker Constants for Intergranular Film in Silicon Nitride from Spatially Resolved-Valence Electron Energy Loss Spectrum Imaging”, Acta Materialia, 46, 7, 2271-87 (1998).
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R. H. French, H. Müllejans, D. J. Jones, "Optical Properties of Aluminum Oxide: Determined from Vacuum Ultraviolet and Electron Energy Loss Spectroscopies", Journal of the American Ceramic Society, 81, 10, 2549-57, (1998).
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Software for Valence EELS Analysis

H. Müllejans, R. H. French, "Insights Into the Electronic Structure of Ceramics Through Quantitative Analysis of Valence Electron Energy-loss Spectroscopy (VEELS)", to be published, Microscopy and Microanalysis.

Abstract

Valence electron energy-loss spectroscopy was performed on six ceramic materials in a dedicated STEM. Quantitative analysis of these data is described yielding access to the complex optical properties and the electronic structure of the materials. Comparisons are made on the basis of the interband transition strength describing transitions between occupied states in the valence band and empty states in the conduction band. This proves that the quantitative analysis of VEEL data is a competitive and complementary method to be considered when investigating the electronic structure of materials. Possibilities for improvement and extension of the analysis are discussed extensively.

Figure 1. VEEL spectra of ceramics, all intensities are in arbitrary units; (e) CaO(Al₂O₃)₆ and (f) b-Si₃N₄.

Figure 2. Real part of the interband transition strength J_CV from data of Figure 1; (a) a-Al₂O₃ (continuous line), g-Al₂O₃ (dashed line) and CaO(Al₂O₃)₆ (dotted line); (b) b-Si₃N₄ (continuous line), MgAl₂O₄ (dashed line) and MgO (dotted line).

Figure 3. Sum rule for data of Figure 2.