CASPIAN JOURNAL
MANAGEMENT AND HIGH TECHNOLOGIES
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Read | Bulatov Marat F., Bulatova Alsu N., Starov Dmitry V., Ilyasov Fardin K. // Caspian journal : management and high technologies. — 2012. — №1. — pp. 131-138. |
Bulatov Marat F. - Doctor of Physical and Mathematical sciences, professor, Astrakhan State University, 414056, Russia, Astrakhan, Tatishcheva 20 a, bulatov_agu@mail.ru.
Bulatova Alsu N. - Candidate of Physical and Mathematical sciences, Astrakhan State University, 414056, Russia, Astrakhan, Tatishcheva 20 a, anbulatova@mail.ru.
Starov Dmitry V. - postgraduate, Astrakhan State University, 414056, Russia, Astrakhan, Tatishcheva 20 a, bortv715ke@mail.ru.
Ilyasov Fardin K. - postgraduate, Astrakhan State University, 414056, Russia, Astrakhan, Tatishcheva 20 a, ilyasov@aspu.ru.
The structure, binding characteristics and low atomic weight, cause a high thermal conductivity of different allotropic modifications of carbon, including diamond, graphite and carbon nanotubes. The research freely suspended graphene sheet showed that this modification of carbon has a high value of thermal conductivity. According to the available experimental data, graphene has the highest thermal conductivity of solids at room temperature. It is known that graphite consists of graphene layers, separated by a distance of about 0,35 nm, while the adjacent layers have a huge impact on the transport of phonons along the graphene layer. The interaction of phonons with the adjacent layers and the substrate with a nickel leads to additional scattering channel, and thus to reduce the thermal conductivity. Our samples, according to Raman spectroscopy, consisted of the areas in which the number of layers varied from 2–3 and more than 14. Highest thermal conductivity of the sample marked #5 (d (Ni) = 150 nm, t = 15 min.). This is due to a small number of layers (2–3) and a small thickness of the nickel film. The mechanism of the thermal conductivity of graphene is related to the propagation of phonons, therefore, coefficient of thermal conductivity determined by the phonon mean free path, or related to the scattering by defects or by phonon-phonon interaction. If this path length exceeds the size of the sample, then the ballistic transport of heat, which skips through the graphene phonons without experiencing scattering.
Key words: graphene,graphene layers,"hot disk",substrate,conditions of synthesis,thermal conductivity,Raman spectroscopy,phonon-phonon interaction,phonon mean free path,ballistic heat transfer