Growth process conditions of vertically aligned carbon nanotubes using plasma enhanced chemical vapor deposition

Chhowalla, Manishkumar; Teo, K. B. K.; Ducati, Caterina; Rupesinghe, N. L.; Amaratunga, G. A. J.; Ferrari, Andrea C.; Roy, Debdulal; Robertson, John; Milne, W. I.

doi:10.1063/1.1410322

Cited by 991 publications

(668 citation statements)

References 38 publications

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“…Upon annealing to the growth temperature in the range 500 to 700 -C, under H 2 flow, with the help of the thermally activated HWCVD process (W filament heated at 1800 -C), the nickel thin film was found to break up into nanoparticles which seed the growth of the MWCNTs. Owing to the studies of other groups [5,7,9], it has been shown that the thickness of the initial Ni thin film and the growth temperature determine the size and density of the nanoparticles formed after annealing, and hence control the diameter and density of the nanotubes. After reaching the working temperature, the nanotube growth was initiated by introducing NH 3 and C 2 H 2 into the chamber and igniting the glow discharge plasma using a 1 kW dc generator between the anode and the heated substrate-holder, the distance between these electrodes being 8 mm.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the hightemperature methods have been replaced by several lowtemperature chemical vapor deposition (CVD) techniques (< 800 -C), which are most promising in terms of CNT deterministic growth. These techniques include thermal CVD [4,5], direct current (dc) plasma-enhanced CVD (dc PECVD) [6,7], microwave PECVD [8 -10], hot-wire (HW) dc PECVD [11 -13], and HWCVD [14 -16]. In all these techniques, substrates (c-Si or SiO 2 coated c-Si) were coated with a suitable transition metal catalyst, primarily Fe, Co or Ni.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of multi-walled carbon nanotubes by combining hot-wire and dc plasma-enhanced chemical vapor deposition

et al. 2006

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Multi-walled carbon nanotubes (MWCNTs) have been grown on 7 nm Ni-coated substrates consisting of crystalline silicon covered with a thin layer (10 nm) of TiN, by combining hot-wire chemical vapor deposition (HWCVD) and direct current plasma-enhanced chemical vapor deposition (dc PECVD), at 620 -C. Acetylene (C 2 H 2 ) gas is used as the carbon source and ammonia (NH 3 ) and hydrogen (H 2 ) are used either for dilution or etching. The carbon nanotubes range from 20 to 100 nm in diameter and 0.3 to 5 Am in length, depending on growth conditions: plasma intensity, filament current, pressure, C 2 H 2 , NH 3 , H 2 flow rates, C 2 H 2 /NH 3 and C 2 H 2 /H 2 mass flow ratios. By combining the HWCVD and the dc PECVD processes, uniform growth of oriented MWCNTs was obtained, whereas by using only the HWCVD process, tangled MWCNTs were obtained. By patterning the nickel catalyst, with the use of the HW dc PECVD process, uniform arrays of nanotubes have been grown as well as single free-standing aligned nanotubes, depending on the catalyst patterning (optical lithography or electron-beam lithography). In the latter case, electron field emission from the MWCNTs was obtained with a maximum emission current density of 0.6 A/cm 2 for a field of 16 V/Am.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of multi-walled carbon nanotubes by combining hot-wire and dc plasma-enhanced chemical vapor deposition

et al. 2006

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“…19,20 Both product yield and the properties of CNTs are basically determined by the raw materials, for example, CNT production has been investigated from laser ablation, plasma assisted deposition, pyrolysis or chemical vapour deposition. 21,22 However, only limited information is available about the pyrolysis of real-world waste plastics for CNT production.…”

Section: Introductionmentioning

confidence: 99%

Processing Real-World Waste Plastics by Pyrolysis-Reforming for Hydrogen and High-Value Carbon Nanotubes

Nahil

Miskolczi

et al. 2013

Environ. Sci. Technol.

181

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Producing both hydrogen and high-value carbon nanotubes (CNTs) derived from waste plastics is reported here using a pyrolysis-reforming technology comprising a two-stage reaction system, in the presence of steam and a Ni-Mn-Al catalyst. The waste plastics consisted of plastics from a motor oil container (MOC), waste commercial high density polyethylene (HDPE) and regranulated HDPE waste containing polyvinyl chloride (PVC). The results show that hydrogen can be produced from the pyrolysis-reforming process, but also carbon nanotubes are formed on the catalyst. However, the content of 0.3 wt.% polyvinyl chloride in the waste HDPE (HDPE/PVC) has been shown to poison the catalyst and significantly reduce the quantity and purity of CNTs. The presence of sulphur has shown less influence on the production of CNTs in terms of quantity and CNT morphologies. Around 94.4 mmol H 2 g -1 plastic was obtained for the pyrolysis-reforming of HDPE waste in the presence of the Ni-Mn-Al catalyst and steam at a reforming temperature of 800 °C. The addition of steam in the process results in an increase of hydrogen production and reduction of carbon yield; in addition, the defects of CNTs e.g. edge dislocations were found to be increased with the introduction of steam (from Raman analysis).

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“…The the nanopores [11], [12]. RIE [10], [13], [15] can reliably and selectively remove the junk carbon layer, but it may take up to 5 hours. Besides, RIE requires rather expensive equipment and sophisticated maintenance, thus is less available outside of large research universities and laboratories.…”

Section: Methodsmentioning

confidence: 99%

“…Numerous attempts, such as air oxidation and reactive ion etching (RIE) [10]- [15] were studied for this purpose. However, each of these methods has their own pros and cons.…”

mentioning

confidence: 99%

Exposure of Carbon Nanotubes Fabricated by Template-Assisted CVD through a Two-Step Method

Yao¹,

Xu²,

Cen³

et al. 2015

IJMMM

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Abstract-Well aligned carbon nanotubes (CNTs) are highly desirable for various studies and applications. Template-assisted chemical vapor deposition has been widely used. However, post growth surface cleaning to remove the junk carbon on sample surface and expose CNTs still relies on either capital intensive facilities or 'hard to control' processes. In the letter, we report a mechanical polishing method to remove the amorphous carbon layer. Compared to other conventional surface cleaning methods, mechanical polishing is relatively straightforward, much easier to scale up and does not require expensive instruments. Combined with a wet-etching step, highly ordered CNT arrays were reliably obtained. Scanning electron microscopy and atomic force microscopy were employed to investigate the surface morphology and roughness and to optimize the processing conditions.

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Growth process conditions of vertically aligned carbon nanotubes using plasma enhanced chemical vapor deposition

Cited by 991 publications

References 38 publications

Synthesis of multi-walled carbon nanotubes by combining hot-wire and dc plasma-enhanced chemical vapor deposition

Synthesis of multi-walled carbon nanotubes by combining hot-wire and dc plasma-enhanced chemical vapor deposition

Processing Real-World Waste Plastics by Pyrolysis-Reforming for Hydrogen and High-Value Carbon Nanotubes

Exposure of Carbon Nanotubes Fabricated by Template-Assisted CVD through a Two-Step Method

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