Monodisperse carbon nanopearls in a foam-like arrangement: a new carbon nano-compound for cold cathodes

Levesque, Alexandra; Binh, Vu Thien; Semet, V.; Guillot, Dominique; Fillit, R.Y.; Brookes, Matthew D.; Nguyen, Thi-Phuong

doi:10.1016/j.tsf.2004.06.012

Cited by 47 publications

(37 citation statements)

References 8 publications

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“…Solid carbon spheres (also known as nanospheres or nanopearls), with sizes ranging from *100 nm to 1 lm, were synthesized by a number of researchers using Chemical Vapor Deposition (CVD) methods [1][2][3][4][5][6][7]. Initially, carbon nanopearls were investigated as potential cathode materials due to their field emission properties [1,[8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Tribological Properties of Carbon Nanopearls Synthesized by Nickel-Catalyzed Chemical Vapor Deposition

et al. 2008

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Section: Introductionmentioning

confidence: 99%

“…Initially, carbon nanopearls were investigated as potential cathode materials due to their field emission properties [1,[8][9][10][11]. However, because of their spherical shape and graphitic structure, carbon nanopearls are also potentially useful for tribological coatings and lubricant additives.…”

Section: Introductionmentioning

confidence: 99%

Tribological Properties of Carbon Nanopearls Synthesized by Nickel-Catalyzed Chemical Vapor Deposition

et al. 2008

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“…Carbon nanofoams usually consist of agglomerations of porous nano-or micron-sized spheres. Such so-called nanoor micro-pearls have been produced by various methods such as laser ablation [48][49][50], chemical vapor deposition (CVD) [39,[51][52][53][54][55][56][57][58][59][60] or hydrothermal carbonization (HTC) [30][31][32][33]46,[61][62][63][64][65][66][67]. In this paper, we show that morphologies other than micropearls can be synthesized just by changing the process parameters.…”

Section: Discussionmentioning

confidence: 99%

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

Frese

Mitchell

Bowers

et al. 2017

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Unusual structure of low-density carbon nanofoam, different from the commonly observed micropearl morphology, was obtained by hydrothermal carbonization (HTC) of a sucrose solution where a specific small amount of naphthalene had been added. Helium-ion microscopy (HIM) was used to obtain images of the foam yielding micron-sized, but non-spherical particles as structural units with a smooth foam surface. Raman spectroscopy shows a predominant sp 2 peak, which results from the graphitic internal structure. A strong sp 3 peak is seen in X-ray photoelectron spectroscopy (XPS). Electrons in XPS are emitted from the near surface region which implies that the graphitic microparticles have a diamond-like foam surface layer. The occurrence of separated sp 2 and sp 3 regions is uncommon for carbon nanofoams and reveals an interesting bulk-surface structure of the compositional units.

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“…This is due to the fact that carbon is one of the best known cold emitters of electrons and the potential cost saving using carbon offers. Intense research is being applied to using carbon nanomaterials as field emitters [49].…”

Section: Applicationsmentioning

confidence: 99%

The electrical transport properties of nitrogen doped carbon microspheres

Wright

Marsicano

Keartland

et al. 2014

Materials Chemistry and Physics

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A suite of four samples of nitrogen doped carbon microspheres, each with a different level of nitrogen dopant, was synthesised in a horizontal chemical vapour deposition reaction. The samples were characterized using scanning electron microscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy. Scanning electron microscopy showed that microspheres were produced by the reaction. Raman spectroscopy confirmed the graphitic nature of the samples. Electron paramagnetic resonance spectroscopy determined that nitrogen was present in the graphitic lattice and was used as a non-destructive technique to measure the amount of substitutional nitrogen present in the samples. In order to perform electrical transport measurements an automated magneto-transport measurement station was developed in the laboratory. This transport station was computer controlled and contained all of the necessary hardware and software required to perform magneto-electrical transport measurements. Variable temperature electrical transport measurements were performed on all samples to determine their conductive properties. Resistance measurements showed that two of the samples were semiconductors while the other two samples displayed a transition to metallic behaviour at higher temperatures. This transition can be ascribed to the thermal desorption of nitrogen dopant. Models were fitted to the data and the semiconducting behaviour is best explained by a model of fluctuation induced tunnelling while the metallic behaviour is best explained by a quasi-1 dimensional metallic term based on electron-phonon interactions. The IV characteristics of two of the samples display increasing non-linearity of the current's voltage dependence with decreasing temperature. The other two samples exhibit this behaviour at lower temperatures while higher temperature IV data displays a current saturation with increasing voltage. The same models used to explain the resistance measurements can be used to explain the IV characteristics data extremely well. The magnetoresistance data taken with the direction of current flow orientated both parallel and perpendicular to the field, show a transition from negative to positive magnetoresistance with decreasing temperature. The results of these experiments are inconclusive, as a theoretical model of magnetoresistance in systems that conduct via fluctuation induced tunnelling is not well defined. A comparison between the resistance measurements of all four samples was made to determine the effect of nitrogen doping on the samples' ii Abstract electronic transport properties. The result of this comparison was indeterminate. This was due to samples with identical nitrogen dopant levels displaying vastly different conductive properties and indicates that very strict synthesis conditions need to be adhered to in order to ensure sample quality. Resistance measurements were rerun on the two samples that displayed purely semiconducting behaviour to investigate the possibility of atmospheric doping. It was foun...

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Monodisperse carbon nanopearls in a foam-like arrangement: a new carbon nano-compound for cold cathodes

Cited by 47 publications

References 8 publications

Tribological Properties of Carbon Nanopearls Synthesized by Nickel-Catalyzed Chemical Vapor Deposition

Tribological Properties of Carbon Nanopearls Synthesized by Nickel-Catalyzed Chemical Vapor Deposition

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

The electrical transport properties of nitrogen doped carbon microspheres

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