Pressure Effects on Single Wall Carbon Nanotube Bundles

Teredesai, Pallavi V.; Sood, Anil K.; Sharma, Surinder M.; Karmakar, S.; Sikka, S. K.; Govindaraj, A.; Rao, C. N. R.

doi:10.1002/1521-3951(200101)223:2<479::aid-pssb479>3.0.co;2-z

Cited by 32 publications

(28 citation statements)

References 27 publications

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“…Experiments with pressure-transmitting media other than alcohol were, unfortunately, limited to maximum pressures of 9 GPa (nitrogen, 33 solid at 2.5 GPa) and 7 GPa (water, 39 solid at ¾1 GPa). Teredesai et al 39 argued that the absence of a phase transition up to 6 GPa in the experiment with water would rule out the possibility that the 10 GPa anomaly could be related to the freezing of the pressure-transmitting medium. For unambiguous evidence that the anomaly is an intrinsic property of carbon nanotubes, the softening should, ideally, be reproduced in an experiment to 15-20 GPa employing a fully hydrostatic pressure-transmitting medium, e.g.…”

Section: Structural Resiliencesupporting

confidence: 61%

“…It should be mentioned that the anomaly may, in principle, be related to the solidification of the pressure-transmitting medium at 10 GPa and the associated occurrence of shear strains above this pressure. Experiments with pressure-transmitting media other than alcohol were, unfortunately, limited to maximum pressures of 9 GPa (nitrogen, 33 solid at 2.5 GPa) and 7 GPa (water, 39 solid at ¾1 GPa). Teredesai et al 39 argued that the absence of a phase transition up to 6 GPa in the experiment with water would rule out the possibility that the 10 GPa anomaly could be related to the freezing of the pressure-transmitting medium.…”

Section: Structural Resiliencementioning

confidence: 88%

“…In armchair tubes, which are always metallic, this anisotropy is expected to result in different pressure derivatives for the frequency of modes with axial and circumferential displacement of the atoms. 55 Teredesai et al, 39 on the other hand, conducted the experiment with excitation at 515 nm, where semiconducting tubes should be in resonance. If a methanol-ethanol-water mixture was used as pressure-transmitting medium, the three most intense I. Loa components shifted at rates of 5.8-6.1 cm 1 GPa 1 , whereas two low-energy, low-intensity components of the T band shifted at 5.3 cm 1 GPa 1 (Fig.…”

Section: Shear Strainmentioning

confidence: 90%

“…8). In contrast, Teredesai et al 39 stated explicitly that they did not observe such change in slope. Finally, Venkateswaran et al 32 and Obraztsova et al 33 reported that broadening of the tangential peaks occurred only for pressures above 2 GPa.…”

Section: Summary Of Experimental Indicationsmentioning

confidence: 99%

“…At variance with this result, Sharma et al 56 could follow the (10) reflection up to ¾10 GPa, and they did not find evidence for a structural transition at 1.7 GPa. The latter finding is in accordance with the fact that Teredesai et al 39 did not observe, on the same type of sample, a change in wavenumber shift of the tangential modes near 1.7 GPa. Likewise, there is no consensus on the question of reversibility of the structural changes.…”

Section: Structural Changesmentioning

confidence: 99%

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Raman spectroscopy on carbon nanotubes at high pressure

Loa

2003

J Raman Spectroscopy

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Raman spectroscopy has been the most extensively employed method to study carbon nanotubes at high pressures. This review covers reversible pressure-induced changes of the lattice dynamics and structure of single- and multi-wall carbon nanotubes as well as irreversible transformations induced by high pressures. The interplay of covalent and van-der-Waals bonding in single-wall nanotube bundles and a structural distortion near 2 GPa are discussed in detail. Attempts of transforming carbon nanotubes into diamond and other "superhard" phases are reviewed critically.Comment: 33 pages, 20 figures, review article, to appear in J. Raman Spectroscop

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Section: Structural Resiliencesupporting

confidence: 61%

Section: Structural Resiliencementioning

confidence: 88%

Section: Shear Strainmentioning

confidence: 90%

Section: Summary Of Experimental Indicationsmentioning

confidence: 99%

Section: Structural Changesmentioning

confidence: 99%

See 3 more Smart Citations

Raman spectroscopy on carbon nanotubes at high pressure

Loa

2003

J Raman Spectroscopy

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single ‐ wall (carbon) nanotubes

2020

Catalysis From a to Z

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The temperature dependence of the Raman spectrum of a gelatine-based composite material doped with single-walled carbon nanotubes (SWNT@gelatin) is reported. A significant up-shift of the G-mode frequency is observed when the temperature is decreased from room temperature to 20 K. This frequency shift is significantly stronger than the one found for pure thermal effects. In contrast, the features of the radial breathing modes (frequencies and width) display no significant change in the same temperature range. These results are well understood by considering a uniaxial strain on the nanotube induced by the thermal expansitivity mismatch between the nanotube and the surrounding matrix.2

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Exfoliation of Single‐Walled Carbon Nanotubes by Electrochemical Treatment in a Nitric Acid

Kim

Jeon

et al. 2003

Advanced Materials

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InP nanowires [20] for polarized light detection, and is attributed to the polarization-dependent light absorption due to the dielectric contrast between the nanowire and its air surroundings. Because of the confinement in the nanowire radial direction, where the nanowire diameter is far smaller than the incident wavelength, an incident electric field that is perpendicular to the nanowire would be effectively attenuated compared to the electric field parallel to the nanowire, therefore leading the observed polarization-dependent photocurrent.[20] The current ratio for parallel and perpendicular excitation is around 4:3, comparable to the ratio obtained with single-walled carbon nanotube polarization infrared detectors. [19] The non-zero current measured with the UV radiation polarized perpendicular to the nanowire is likely caused by depolarization of light when scattered by the nearby metal electrodes. Theoretical simulations are currently underway for a better understanding. We stress that our results represent a significant step toward using nanowires as polarized UV detectors and further optimization will lead to even better performance. In summary, high-quality and large-quantity tin oxide nanowires were synthesized using a laser ablation technique and their composition and single crystalline structures were confirmed using XRD, TEM, and SAED. The growth mechanism was confirmed to follow the vapor±liquid±solid model. Precise control over the nanowire diameter was achieved by using mono-dispersed gold clusters as the catalyst. Field-effect transistors were made based on our SnO 2 nanowires, and excellent n-type transistor characteristics have been observed with threshold voltages~± 50 V and on/off ratios of~10 3 at room temperature. Photoconduction properties of SnO 2 nanowires were also studied based on our devices, where a strong modulation of the conductance by UV illumination was observed. Typical devices showed substantial increases in conductance up to four orders of magnitude upon UV illumination. SnO 2 nanowire transistors have furthermore been found to work as polarized UV detectors. ExperimentalTin oxide nanowires were prepared using a pulsed Nd:YAG laser with a repetition rate of 10 Hz and a pulse power of 1.0 W. A pure Sn (Alfa Aeser, 99.995 %) target was mounted at the upper-stream of a quartz tube furnace and then ablated to supply the vapor, which was carried downstream by diluted oxygen in argon. SiO 2 ±Si substrates coated with Au nanoparticles were placed at the downstream of the tube furnace with the Au particles serving as the catalyst for growth. The reaction was typically carried out around 900 C for 10±30 min with 100 standard cubic centimeters per minute Ar±O 2 mixture flowing. The chamber pressure was controlled at 400 torr during the growth.The as-synthesized nanowires were characterized and identified using XRD (Rigaku RV-120 apparatus, Cu Ka = 1.5418 radiation), SEM (Philips XL30 apparatus operated at 15 keV), and TEM (Phillips 420 apparatus operated at 120 keV).SnO 2 nanowires fie...

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Pressure Effects on Single Wall Carbon Nanotube Bundles

Cited by 32 publications

References 27 publications

Raman spectroscopy on carbon nanotubes at high pressure

Raman spectroscopy on carbon nanotubes at high pressure

single ‐ wall (carbon) nanotubes

Exfoliation of Single‐Walled Carbon Nanotubes by Electrochemical Treatment in a Nitric Acid

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