KFU. Card publication. Water-Anchored Edge Defects in Amorphous Carbon Probed with Thermal- and Electroassisted Raman Spectroscopy and Nanoscopy

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WATER-ANCHORED EDGE DEFECTS IN AMORPHOUS CARBON PROBED WITH THERMAL- AND ELECTROASSISTED RAMAN SPECTROSCOPY AND NANOSCOPY

Form of presentation

Articles in international journals and collections

Year of publication

2020

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Authors, employees of KFU

Saparina Svetlana Vyacheslavovna, author

Fishman Aleksandr Izrailovich, author

Kharincev Sergey Sergeevich, author

Other authors

Li Jie , author

Stolov Andrei , author

Bibliographic description in the original language

Kharintsev S.S.Water-Anchored Edge Defects in Amorphous Carbon Probed with Thermal- and Electroassisted Raman Spectroscopy and Nanoscopy //S.S.Kharintsev, S.V.Saparina, A.I.Fishman, A.A.Stolov, J.Li //The Journal of Physical Chemistry C.-2020.-124, 29.-15886-15894

Annotation

As-thermal-CVD-synthesized amorphous carbon (a-C) ultrathin coatings enable silica optical fibers to be mechanically robust and optically transparent in aggressive environments. This is achieved by mitigating both hydrogen diffusion and water ingression onto the fiber surface. Notwithstanding the advanced performance of CVD-deposited a-C films, their functionality may suffer from structural and topology defects, dopants, intrinsic stresses, and other imperfections. In this paper, we experimentally study the influence of water-anchored edge functional groups on dc electrical conductivity and Raman scattering of a-C films, ranging from 10 to 100 nm in thickness, exposed to thermal and electrical annealing. A series of heating/cooling cycles was found to affect the disorder D-family bands in the Raman spectra of a-C. In particular, two new Raman peaks at 1260 and 1400 cm–1, attributed to carboxyl (COOH) and hydroxyl (C–OH) groups, have been unraveled through polarization-controlled far-field Raman spectroscopy and tip-enhanced Raman scattering (TERS) spectroscopy. The TERS technique allows one to readily resolve the broad disorder D-family bands due to the excitation of coherent Raman scatters (nanosized graphitic clusters). A temperature-sensitive and thickness-dependent hysteresis in dc conductivity, observed at temperatures of above 80 ?C, is explained by physical sorption/desorption of water at the surface of graphite-like crystals through hydrogen bonding and dissociative absorption of water with the formation of extra COOH/C–OH groups at the edge defects. The electroheating leads to a nonuniform distribution of the water-decorated edges owing to hot spots of a percolated carbon crystals network. This is directly evidenced by electroassisted TERS mapping of the a-C coating. We believe that our study will pave a way for the understanding of how water interacts with amorphous carbon and improve the performance of carbon coatings in harsh environments.

Keywords

amorphous carbon,optical fibers, Raman scattering

The name of the journal

J CHEM PHYS

Please use this ID to quote from or refer to the card

https://repository.kpfu.ru/eng/?p_id=242693&p_lang=2

Full metadata record

Field DC	Value	Language
dc.contributor.author	Saparina Svetlana Vyacheslavovna	ru_RU
dc.contributor.author	Fishman Aleksandr Izrailovich	ru_RU
dc.contributor.author	Kharincev Sergey Sergeevich	ru_RU
dc.contributor.author	Li Jie	ru_RU
dc.contributor.author	Stolov Andrei	ru_RU
dc.date.accessioned	2020-01-01T00:00:00Z	ru_RU
dc.date.available	2020-01-01T00:00:00Z	ru_RU
dc.date.issued	2020	ru_RU
dc.identifier.citation	Kharintsev S.S.Water-Anchored Edge Defects in Amorphous Carbon Probed with Thermal- and Electroassisted Raman Spectroscopy and Nanoscopy //S.S.Kharintsev, S.V.Saparina, A.I.Fishman, A.A.Stolov, J.Li //The Journal of Physical Chemistry C.-2020.-124, 29.-15886-15894	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/eng/?p_id=242693&p_lang=2	ru_RU
dc.description.abstract	J CHEM PHYS	ru_RU
dc.description.abstract	As-thermal-CVD-synthesized amorphous carbon (a-C) ultrathin coatings enable silica optical fibers to be mechanically robust and optically transparent in aggressive environments. This is achieved by mitigating both hydrogen diffusion and water ingression onto the fiber surface. Notwithstanding the advanced performance of CVD-deposited a-C films, their functionality may suffer from structural and topology defects, dopants, intrinsic stresses, and other imperfections. In this paper, we experimentally study the influence of water-anchored edge functional groups on dc electrical conductivity and Raman scattering of a-C films, ranging from 10 to 100 nm in thickness, exposed to thermal and electrical annealing. A series of heating/cooling cycles was found to affect the disorder D-family bands in the Raman spectra of a-C. In particular, two new Raman peaks at 1260 and 1400 cm–1, attributed to carboxyl (COOH) and hydroxyl (C–OH) groups, have been unraveled through polarization-controlled far-field Raman spectroscopy and tip-enhanced Raman scattering (TERS) spectroscopy. The TERS technique allows one to readily resolve the broad disorder D-family bands due to the excitation of coherent Raman scatters (nanosized graphitic clusters). A temperature-sensitive and thickness-dependent hysteresis in dc conductivity, observed at temperatures of above 80 ?C, is explained by physical sorption/desorption of water at the surface of graphite-like crystals through hydrogen bonding and dissociative absorption of water with the formation of extra COOH/C–OH groups at the edge defects. The electroheating leads to a nonuniform distribution of the water-decorated edges owing to hot spots of a percolated carbon crystals network. This is directly evidenced by electroassisted TERS mapping of the a-C coating. We believe that our study will pave a way for the understanding of how water interacts with amorphous carbon and improve the performance of carbon coatings in harsh environments.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject	amorphous carbon	ru_RU
dc.subject	optical fibers	ru_RU
dc.subject	Raman scattering	ru_RU
dc.title	Water-Anchored Edge Defects in Amorphous Carbon Probed with Thermal- and Electroassisted Raman Spectroscopy and Nanoscopy	ru_RU
dc.type	Articles in international journals and collections	ru_RU