Synthesis of Aligned Carbon Nanofibers at 200<sup>°</sup>C

Lee, Kuei‐Yi; Katayama, Mitsuhiro; Honda, Shinya; Kuzuoka, Takashi; Miyake, Takashi; Terao, Yasuhiro; Lee, Jung Goo; Mori, Hirotarô; Hirao, Takashi; Oura, Kenjiro

doi:10.1143/jjap.42.l804

Cited by 24 publications

(13 citation statements)

References 4 publications

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“…Although such hot spots were not identified by thermography, local plasma heating is highly anticipated which eventually promotes reaction between adsorbed CO 2 and neighboring carbonaceous species. Another possibility is the chemical etching by active hydrogen [61]. This phenomena is well investigated in carbon nanotube growth [62,63].…”

Section: Comparison With Thermal Reactionmentioning

confidence: 99%

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

et al. 2015

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Section: Comparison With Thermal Reactionmentioning

confidence: 99%

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

et al. 2015

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“…Thus, PECVD allows nanotubes to been grown at lower temperatures. [11][12][13][14][15][16][17][18][19][20] For example, Hofmann et al 12 13 observed that the low-power plasma-enhanced chemical vapor deposition (PECVD) of MWNTs using Ni, Co or Fe as a catalyst and acetylene/ ammonia mixture as growth gas gave a growth activation energy of order 0.23 eV (Fig. 2), which is much lower than that found by simple thermal CVD.…”

Section: Low Temperature Growthmentioning

confidence: 99%

Controlling the Catalyst During Carbon Nanotube Growth

Robertson¹,

Hofmann²,

Cantoro³

et al. 2008

j nanosci nanotechnol

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We have recently been able to grow single-walled carbon nanotubes by purely thermal chemical vapour deposition (CVD) at temperatures as low as 400 degrees C. This has been achieved by separating the catalyst pre-treatment step from the growth step. In the pre-treatment step, a thin film catalyst is re-arranged into a series of nano-droplets, which are then the active catalysts. Both steps have been studied by in-situ environmental transmission electron microscopy and X-ray photoemission spectroscopy. We have also studied the catalyst yield, the weight of nanotubes grown per weight of transition metal catalyst. Using very thin layers of Fe on Al2O3 support in a remote plasma-assisted CVD, we have achieved yields of order 100,000. This may be due to control of catalyst poisoning by ensuring an etching path.

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“…This paper was presented at the AVS 51st International Symposium held in Anaheim CA, November [14][15][16][17][18][19]2004. NSC-92-2622-E-007-016.…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…5 In the catalytic CVD processes, a gas mixture containing hydrocarbon precursors serving as carbon sources for CNT growth such as methane ͑CH 4 ͒ or acetylene ͑C 2 H 2 ͒ and a second gas such as hydrogen ͑H 2 ͒ or ammonia ͑NH 3 ͒ for maintaining catalysts active by etching away amorphous carbon ͑a-C͒ deposits are often employed. [16][17][18] The measurements of these plasma properties can also enhance our understanding of the basic physical and chemical mechanisms associated with catalytic synthesis of CNTs. 13 For plasmaenhanced processes, the relative concentration of different chemical species is also strongly correlated with electron temperature, in addition to the plasma density.…”

Section: Introductionmentioning

confidence: 99%

Experimental characterization of an inductively coupled acetylene/hydrogen plasma for carbon nanofiber synthesis

Lin

Wei

Leou

et al. 2006

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inCarbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers J. Appl. Phys. 113, 024313 (2013); 10.1063/1.4774218On the growth of carbon nanofibers on glass with a Cr layer by inductively coupled plasma chemical vapor deposition: The effect of Ni film thickness Effect of high-voltage sheath electric field and ion-enhanced etching on growth of carbon nanofibers in highdensity plasma chemical-vapor deposition J. Appl. Phys. 98, 044313 (2005);A plasma-enhanced chemical-vapor deposition process was employed to synthesize carbon nanofibers ͑CNFs͒ on glass substrates patterned with Ni catalytic films. At the gas pressure of 20 mTorr and the substrate temperature ͑surface͒ of ϳ500°C, the isolated and vertically aligned carbon nanofibers have been successfully synthesized. This paper reports experimental investigation of plasma properties characterized by the optical emission spectroscopy of the spectral line intensities of the various species such as hydrogen, C 2 , and CH, as well as the rf characteristics at the biased substrate stage measured by an impedance meter. The measurement results reveal that the C 2 density increases with the acetylene/hydrogen flow ratio and the inductively coupled plasma ͑ICP͒ source power, as expected. The atomic hydrogen density, however, decreases with the flow ratio but increases with the ICP power. The resulting growth rate of CNFs increases with the C 2 density if atomic hydrogen density also increases accordingly, e.g., as the ICP power increases. The trend is reversed if the atomic hydrogen density decreases, due to too much amorphous carbon ͑a-C͒ layer formed as a result of oversupply of carbon but not enough atomic hydrogen to remove a-C. The experimental results also show that the etch effect upon the effective removing of the a-C on the surface of catalytic nanoparticles is further enhanced by ion bombardment, e.g., when either the flux ͑or current͒ or energy of the ions incident on the substrate surface increases, to give rise to an increase in growth rate. In our ICP reactor, the ion current increases with the ICP power, but it changes little when the bias power is varied. The ion energy increases with the bias power, but it decreases as the ICP power increases while the bias power is fixed. The latter one is because the plasma density increases with the inductively coupled plasma power.

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Synthesis of Aligned Carbon Nanofibers at 200^°C

Cited by 24 publications

References 4 publications

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

Controlling the Catalyst During Carbon Nanotube Growth

Experimental characterization of an inductively coupled acetylene/hydrogen plasma for carbon nanofiber synthesis

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Synthesis of Aligned Carbon Nanofibers at 200°C

Cited by 24 publications

References 4 publications

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

Pulsed dry methane reforming in plasma-enhanced catalytic reaction

Controlling the Catalyst During Carbon Nanotube Growth

Experimental characterization of an inductively coupled acetylene/hydrogen plasma for carbon nanofiber synthesis

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Synthesis of Aligned Carbon Nanofibers at 200^°C