C sp2/sp3 hybridisations in carbon nanomaterials – XPS and (X)AES  study

Lesiak, Beata; Kövér, László; Tóth, József; Zemek, Josef; Jiricek, Petr; Kromka, Alexander; Rangam, N.

C sp2/sp3 hybridisations in carbon nanomaterials – XPS and (X)AES study

dc.contributor.author	Lesiak, Beata
dc.contributor.author	Kövér, László
dc.contributor.author	Tóth, József
dc.contributor.author	Zemek, Josef
dc.contributor.author	Jiricek, Petr
dc.contributor.author	Kromka, Alexander
dc.contributor.author	Rangam, N.
dc.contributor.organization	Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland	en
dc.contributor.organization	Institute for Nuclear Physics, Hungarian Academy of Sciences, Debrecen, Hungary	en
dc.contributor.organization	Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic	en
dc.date.accessioned	2022-03-29T14:44:59Z
dc.date.available	2022-03-29T14:44:59Z
dc.date.issued	2018-05-05
dc.description.abstract	Shape of the C KLL (KVV) Auger spectrum provides a measure of C sp2/sp3 hybridisations, alternative to C 1s spectra fitting. Due to a smaller kinetic energy of C KLL electrons than C 1s photoelectrons the investigated information depths are attributed to higher or lower surface sensitivity, respectively. Shape of the KLL Auger spectrum of carbon nanostructures reflects density of electronic states (DOS) and contains contributions of sp2 (graphite) and/or sp3 (diamond) hybridisations, whereas for oxygen and hydrogen containing nanostructures this shape reflects chemical effects. C sp2/sp3 content is evaluated from parameter D, which is defined as an energy difference between the maximum and minimum of the first-derivative C KLL spectrum, where dependence of parameter D on C sp2/sp3 hybridisations is assumed to be linear between the D values of graphite and diamond. Derived values of parameter D and therefore C sp2/sp3 hybridisations were found to be influenced by procedure of smoothing the Auger spectra and D values used for reference materials with pure sp3 and pure sp2 hybridisations. Purpose of this work was to estimate reliability of C sp2/sp3 hybridisations derived from parameters D determined for a set of carbon nanomaterials and study the chemical and morphological effects on the measured parameter D values. Presence of an inhomogeneous distribution of hybridisation as a function of depth from the surface was identified mainly in graphene oxides in contrast to graphite and reduced graphene oxide. The largest influence on parameter D and then evaluated C sp2/sp3 content resulted from oxygen and hydrogen at the surface and applied smoothing procedure in contrary to structural properties of carbon nanomaterials (crystallinity, grain size). Values of parameter D for C sp3 and C sp2 hybridisations, i.e. 13.2 eV and 23.1 eV, respectively, are recommended to be used for linear interpolation proposed by Lascovich et al.	en
dc.identifier.citation	B. Lesiak, L. Kövér, J. Tóth, J. Zemek, P. Jiricek, A. Kromka, N. Rangam, C sp2/sp3 hybridisations in carbon nanomaterials – XPS and (X)AES study. Applied Surface Science, 452, 2018, Pages 223-231. https://doi.org/10.1016/j.apsusc.2018.04.269. (https://www.sciencedirect.com/science/article/pii/S0169433218312686)	en
dc.identifier.doi	10.1016/j.apsusc.2018.04.269
dc.identifier.uri	https://open.icm.edu.pl/handle/123456789/21210
dc.language.iso	en
dc.publisher	Elsevier	en
dc.rights	Attribution-NonCommercial-NoDerivatives 4.0 Międzynarodowe	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/	*
dc.subject	C KVV (KLL) spectrum	en
dc.subject	parameter D	en
dc.subject	C sp2/sp3 hybridisations	en
dc.subject	value of parameter D for sp3 and sp2 standards	en
dc.subject	deviations	en
dc.title	C sp2/sp3 hybridisations in carbon nanomaterials – XPS and (X)AES study	en
dc.type	article	en