Size and temperature dependence of the specific heat capacity of carbon nanotubes

Hepplestone, Steven P.; Ciavarella, A.; Janke, C.; Srivastava, G. P.

doi:10.1016/j.susc.2005.12.070

Cited by 79 publications

(44 citation statements)

References 8 publications

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“…As the temperature rises the 1 st optical subband g SW (30 K) is being occupied and the character of the dependence C(T) changes from one -dimensional to quasi -two -dimensional. According to theory [1,2], in this case the crossover temperature T c increases as the SWNT diameter decreases. T c can be estimated as T c  E 1 sub /6k B , where k B is the Boltzmann constant [8,11].…”

Section: Resultsmentioning

confidence: 97%

The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

Bagatskii

Barabashko

Долбин

et al. 2012

Low Temperature Physics

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The specific heat at constant pressure C(T) of bundles of single-walled carbon nanotubes (SWNTs) closed at their ends has been investigated in a temperature interval of 2 -120 K. It is found that the curve C(T) has features near 5 K, 36 K, 80 K and 100 K. The experimental results on the C(T) and the radial thermal expansion coefficient  R (T) of bundles of SWNTs oriented perpendicular to the sample axis have been compared. It is found that the curves C(T) and  R (T) exhibit a similar temperature behavior at T>10 K. The temperature dependence of the Gruneisen coefficient (Т) has been calculated. The curve (Т) also has a feature near 36 K. Above 36 K the Gruneisen coefficient is practically independent of temperature (4). Below 36 K (Т) decreases monotonically with lowering temperature and becomes negative at T< 6 K. PACS: 65.40.Ba Heat capacity; 65.80.-g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems; 81.07.De Nanotubes.

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Section: Resultsmentioning

confidence: 97%

The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

Bagatskii

Barabashko

Долбин

et al. 2012

Low Temperature Physics

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“…This model is more realistic than previous random walk models, because it can take into account CNT-CNT contact points that are Parallel and perpendicular to the CNT direction CNT-CNT contact With and without inter-CNT contact a Thermal boundary resistance R bd is calculated from Eq.1; epoxy density is 1.97 g/cm 3 [25]; epoxy specific heat is 0.97 J/gK [25] and sound velocity is 2400 m/s [26]. b f CN-CN is calculated from Eq.1; SWNT density is 1.3 g/cm 3 [22]; sound velocity in SWNTs is 8,000 m/s [23] and SWNT specific heat is 0.625 J/gK [24]. The same f CN-CN is assumed for the MWNTs due to unavailable experimental data.…”

Section: Discussionmentioning

confidence: 99%

Inter-carbon nanotube contact in thermal transport of controlled-morphology polymer nanocomposites

et al. 2009

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Directional thermal conductivities of aligned carbon nanotube (CNT) polymer nano-composites were calculated using a random walk simulation with and without intercarbon nanotube contact effects. The CNT-contact effect has not been explored for its role in thermal transport, and it is shown here to significantly affect the effective transport properties including anisotropy ratios. The primary focus of the paper is on the non-isotropic heat conduction in aligned-CNT polymeric composites, because this geometry is an ideal thermal layer as well as it constitutes a representative volume element of CNT-reinforced polymer matrices in hybrid advanced composites under development. The effects of CNT orientation, type (single vs. multi-wall), inter-CNT contact, volume fraction and thermal boundary resistance on the effective conductivities of CNT-composites are quantified. It is found that when the CNT-CNT thermal contact is taken into account, the maximum effective thermal conductivity of the nanocomposite decreases ~4 times and ~2 times for the single-walled and the multi-walled CNTs, respectively, at 20% CNT volume fraction.

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“…Our TRIM simulation for irradiation of a bulk target indicates that a 30-keV Ar + ion transfers 800 eV/ion/nm to carbon atoms lying between the surface and a depth of 20 nm. For a (10,10) nanotube, and using [28] c v = 600 J/kg K for the specific heat of SWNTs, this means that an Ar + ion would heat a 13-nm portion of a nanotube to a temperature of 500 • C. Such temperatures are sufficient to cause substantial annealing of defects and desorption of adsorbed impurities. It is clear that propagation of heat further into the sample (beyond the stopping range of the ions) would raise temperatures sufficiently for annealing effects considerably deeper than the penetration depth of the ions, depending on the heat conductivity and other factors.…”

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Ion irradiation effects on conduction in single-wall carbon nanotube networks

et al. 2008

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We have measured how irradiation by Ar + and N + ions modifies electronic conduction in single-wall carbon nanotube (SWNT) networks, finding dramatically different effects for different thicknesses. For very thin transparent networks, ion irradiation increases localization of charge carriers and reduces the variable-range hopping conductivity, especially at low temperatures. However, for thick networks (SWNT paper) showing metallic conductivity, we find a relatively sharp peak in conductivity as a function of irradiation dose. Our investigation of this peak reveals the important role of thermal annealing extending beyond the range of the irradiating ions, and shows the dependence on the morphology of the samples. We propose a simple model that accounts for the temperature-dependent conductivity. Recently, the effect of defects on the conducting properties of individual metallic single-wall carbon nanotubes (SWNTs) was shown [1,2] by the controlled reduction of the electronic localization length by irradiation with Ar + ions. For these SWNTs in the strong Anderson localization regime, the exponential increase of resistance with length of SWNTs between electrodes was greatly enhanced by di-vacancies created by the Ar + ions. In this paper, we report the first measurements (to our knowledge) of the effect of irradiation by ions on conduction in thin transparent SWNT networks, finding that resistance always increases on ion irradiation. In contrast to these results, however, we show that ion irradiation initially decreases the resistance of our thick SWNT networks.Many applications proposed for carbon nanotubes [3][4][5][6] are likely to be sensitive to irradiation effects, which u Fax: +49-711-689-1010, E-mail: v.skakalova@fkf.mpg.de would be particularly significant, for example, for devices used in space or other high-radiation environments. Controlled irradiation also has many applications related to carbon nanotubes. It has been demonstrated by experimental and theoretical studies that irradiation can be used for nano-engineering of carbon nanotubes [7,8]. For example, focused electron beams were shown to result in welding of crossed single-wall carbon nanotubes to form molecular junctions [9], and molecular dynamics simulations showed how such junctions might also be produced by irradiation by Ar + ions [10]. Irradiation by 1.25-MeV electrons at high temperature (800 • C) was able to coalesce neighbouring Ndoped SWNTs as a result of defect formation followed by thermal annealing [11]. Using irradiation by Ar + ions, Stahl et al. [12] introduced defects in the SWNTs in the upper part of a bundle of loosely coupled SWNTs before depositing gold contacts on top of the bundle. They found that to avoid the defects, the current switched to undamaged nanotubes in the lower part of the bundle, tunnelling being the transfer mechanism between nanotubes.In previous work [13], we observed local modifications of the electronic structure in atomically resolved scanning tunnelling microscope (STM) images of multi-wal...

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Size and temperature dependence of the specific heat capacity of carbon nanotubes

Cited by 79 publications

References 8 publications

The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

Inter-carbon nanotube contact in thermal transport of controlled-morphology polymer nanocomposites

Ion irradiation effects on conduction in single-wall carbon nanotube networks

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