Analytical Sciences

Electron Spectra Line Shape Analysis of Highly Oriented Pyrolytic Graphite and Nanocrystalline Diamond

Beata LESIAK,*¹ Josef ZEMEK,*² Jana HOUDKOVA,*² Alexander KROMKA,*² and Adam JÓZWIK*^3,*⁴

*1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
*2 Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162-53 Prague 6, Czech Republic
*3 Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 02-109 Warsaw, Poland
*4 Computer Engineering Department, Technical University of Lódz, Stefanowskiego 18/22, 90-924 Lódz, Poland

The X-ray excited Auger electron spectroscopy (XAES), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES) methods were applied in investigating samples of nanocrystalline diamond and highly oriented pyrolytic graphite of various C sp²/sp³ ratios, crystallinity conditions and grain sizes. The composition at the surface was estimated from the XPS. The C sp²/sp³ ratio was evaluated from the width of the XAES first derivative C KLL spectra and from fitting of XPS C 1s spectra into components. The pattern recognition (PR) method applied for analyzing the spectra line shapes exhibited high accuracy in distinguishing different carbon materials. The PR method was found to be a potentially useful approach for identification, especially important for technological applications in fields of materials engineering and for controlling the chemical reaction products during synthesis.

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