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UV Raman spectroscopy of segregated carbon in silicon oxycarbides

Roth, Felix and Waleska, Philipp S. and Hess, Christian and Ionescu, Emanuel and Nicoloso, Norbert (2016):
UV Raman spectroscopy of segregated carbon in silicon oxycarbides.
In: Journal of the Ceramic Society of Japan, pp. 1042-1045, 124, (10), [Online-Edition: http://dx.doi.org/10.2109/jcersj2.16100],
[Article]

Abstract

Polymer-derived silicon oxycarbides exhibiting ≤1 and 10 vol.% of segregated carbon finely dispersed within a glassy SixOyCz matrix have been investigated by UV Raman spectroscopy using a laser excitation of 4.8 eV (λ = 256.7 nm). Carbon exists as amorphous sp2–sp3 bonded component in SiOC/C (≤1 vol.%) pyrolyzed at 1100°C in H2, including C–C single bonds, polymeric chains and small polycyclic aromatic hydrocarbons (PAHs). The formation of nanocrystalline carbon at T > 1400°C is seen in the Raman spectra of SiOC/C (≤1 vol.%) and SiOC/C (10 vol.%) by the appearance of the G band of graphite. Tempering at 1600°C increases the degree of order within the carbon phase. However, the slight narrowing of the G peak with processing temperature (by about 5%) indicates still not well-crystallized carbon: the Raman results can be best explained by turbostratic carbon (with a lateral size La of ≈2 nm) and do not support the model description in literature as a network of single layer graphene.

Item Type: Article
Erschienen: 2016
Creators: Roth, Felix and Waleska, Philipp S. and Hess, Christian and Ionescu, Emanuel and Nicoloso, Norbert
Title: UV Raman spectroscopy of segregated carbon in silicon oxycarbides
Language: English
Abstract:

Polymer-derived silicon oxycarbides exhibiting ≤1 and 10 vol.% of segregated carbon finely dispersed within a glassy SixOyCz matrix have been investigated by UV Raman spectroscopy using a laser excitation of 4.8 eV (λ = 256.7 nm). Carbon exists as amorphous sp2–sp3 bonded component in SiOC/C (≤1 vol.%) pyrolyzed at 1100°C in H2, including C–C single bonds, polymeric chains and small polycyclic aromatic hydrocarbons (PAHs). The formation of nanocrystalline carbon at T > 1400°C is seen in the Raman spectra of SiOC/C (≤1 vol.%) and SiOC/C (10 vol.%) by the appearance of the G band of graphite. Tempering at 1600°C increases the degree of order within the carbon phase. However, the slight narrowing of the G peak with processing temperature (by about 5%) indicates still not well-crystallized carbon: the Raman results can be best explained by turbostratic carbon (with a lateral size La of ≈2 nm) and do not support the model description in literature as a network of single layer graphene.

Journal or Publication Title: Journal of the Ceramic Society of Japan
Volume: 124
Number: 10
Uncontrolled Keywords: UV Raman spectroscopy, Carbon, Graphite, Graphene, Nanocomposites, Polymer-derived ceramics
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 14 Sep 2016 05:31
Official URL: http://dx.doi.org/10.2109/jcersj2.16100
Identification Number: doi:10.2109/jcersj2.16100
Funders: Financial support by the Deutsche Forschungs- gemeinschaft (DFG, Ri 510 / 52-1 and INST, 163 / 130-1 FUGG) is gratefully acknowledged.
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