Fabrication of graphene layers from multiwalled carbon nanotubes using high dc pulse

Kim, Woo Sik; Moon, Seong‐Yong; Bang, Sin Young; Choi, Bong Geun; Ham, Heon; Sekino, Tohru; Shim, Kwang Bo

doi:10.1063/1.3213350

Cited by 41 publications

(39 citation statements)

References 19 publications

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“…However, the method was limited to nanoribbons formation on substrates. More recently, unzipping methods such as catalytic cutting 17 and high current pulse burning 18 have been reported, but the quality and yield of nanoribbons were unknown. Thus far, a method capable of producing large amounts of high quality nanoribbons is still lacking.…”

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confidence: 99%

Facile synthesis of high-quality graphene nanoribbons

Jiao¹,

Wang²,

Diankov³

et al. 2010

Nature Nanotech

774

587

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Graphene nanoribbons have attracted attention for their novel electronicand spin transport properties [1][2][3][4][5][6] , and because nanoribbons less than 10 nm wide have a band gap that can be used to make field effect transistors 1-3 . However, producing nanoribbons of very high quality, or in high volumes, remains a challenge 1, 4-18 . Here, we show that pristine few-layer nanoribbons can be produced by unzipping mildly gas-phase oxidized multiwalled carbon nanotube using mechanical sonication in an organic solvent. The nanoribbons exhibit very high quality, with smooth edges (as seen by high-resolution transmission electron microscopy), low ratios of disorder to graphitic Raman bands, and the highest electrical conductance and mobility reported to date (up to 5e 2 /h and 1500 cm 2 /Vs for ribbons 10-20 nm in width). Further, at low temperature, the nanoribbons exhibit phase coherent transport and Fabry-Perot interference, suggesting minimal defects and edge roughness. The yield of nanoribbons was ~2% of the starting raw nanotube soot material, which was significantly higher than previous methods capable of producing high quality narrow nanoribbons 1 . 2The relatively high yield synthesis of pristine graphene nanoribbons will make these materials easily accessible for a wide range of fundamental and practical applications. Fig S1). The yield of nanoribbons was estimated to be ~2 % of the starting raw soot material through the two step process, which could be further improved by repeating the unzipping process for remaining nanotubes in the centrifuged aggregate, increasing the calcination temperature and prolonging the sonication time. The yield and quantity of high quality nanoribbons (width 10-30 nm) far exceeds previous methods capable of making high quality nanoribbons 1,13 .We used atomic force microscope (AFM) to characterize multiwalled carbon nanotubes and the unzipped products deposited on SiO 2 /Si substrates. Nanoribbons were easily distinguished from multiwalled carbon nanotubes due to obvious decreases in apparent heights (1-2.5 nm in height for nanoribbons, Fig Our method produced a high percentage of nanoribbons with ultra-smooth edges by simple calcination and sonication steps, which can be performed in many laboratories. The mechanism of the unzipping differs from previous methods that involved extensive solution-phase oxidation 14 . We proposed that our calcination step led to gas phase-oxidation of pre-existing defects on arc-discharge grown multiwalled carbon nanotubes. A low density structural defect was known to exist on the sidewalls and the ends of high quality arc-derived multiwalled carbon nanotubes 19. The defects and ends were more reactive with oxygen than pristine sidewalls during 500 o C calcination, a condition used for purifying arc-discharge multiwalled carbon nanotubes without introducing new defects on sidewalls 19,20 . Similar to oxidation of defects in the plane of graphite by oxygen 21,22 , etch pits were formed at the defects 5 and extended from the outmost sidewall ...

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confidence: 99%

Facile synthesis of high-quality graphene nanoribbons

Jiao¹,

Wang²,

Diankov³

et al. 2010

Nature Nanotech

774

587

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“…At first sight, the spontaneous formation of CNTs from bilayer graphene nanoribbons is counterintuitive because this is the reverse of a known process in which CNTs can unzip to form GNRs. [18][19][20][21][22][23][24] However, the experiments demonstrating the latter were performed on relatively wide-diameter CNTs, whereas in Ref. 41, it is noted that the formation of CNTs from free-standing bilayer graphene nanoribbons is energetically favored only for nanoribbons of width less than 3 nm.…”

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confidence: 99%

“…For example, CNTs grown using arc discharge, laser ablation, or chemical vapor deposition typically possess a mixture of chiralities and the more exotic structures usually appear only by chance. On the other hand, the synthesis of graphene nanoribbons (GNRs) is more deterministic and can be achieved using lithographic, [9][10][11] chemical, [12][13][14][15] and sonochemical 16,17 techniques, unzipping CNTs [18][19][20][21][22][23][24] and assembling GNRs from chemical precursors. 25 For example, scanning tunneling microscopy (STM) lithography 26 can be used to cut GNRs with widths as small as 2.5 nm, with a specified chirality, a specified location, and with their ends contacted to (graphene) electrodes.…”

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Sculpting molecular structures from bilayer graphene and other materials

et al. 2012

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We demonstrate a technique for creating unique forms of pure sp 2 -bonded carbon and unprecedented heteromolecules. These new structures, which we refer to as sculpturenes, are formed by sculpting selected shapes from bilayer graphene, heterobilayers, or multilayered materials and allowing the shapes to spontaneously reconstruct. The simplest sculpturene is topologically equivalent to a torus, with dimensions comparable to those of fullerenes. The topology of these new molecular structures is stable against atomic-scale defects. We demonstrate that sculpturenes can form the basic building blocks of hollow, multiconnected structures, with potential applications to nanofluidics and nanoelectronics.

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“…Graphene-based sheets have been shown to be very promising for high-performance nanoelectronics, transparent conductors, polymer composites, and microscopy support, etc. Currently, various methods have been developed for production of graphene, including chemical vapor deposition (CVD) [3], micromechanical exfoliation of graphite [4], epitaxial growth on electrically insulating surfaces such as SiC [5], physical method [6], and chemical processing [7]. Among them, the chemical approach is the most suitable method for economically producing graphene sheets on a large scale.…”

Section: Introductionmentioning

confidence: 99%

CATALYST–FREE GROWTH OF WELL–ALIGNED ZnO NANOWIRES ON GRAPHENE/Si SUBSTRATEBY THERMAL EVAPORATION

Khai¹

2018

JST

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Vertically well-aligned ZnO nanowire (NW) arrays with high density were directly synthesized on graphene/Si substrate by thermal evaporation of zinc powder without catalysts or additives. The ZnO NWs were characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), photoluminescence (PL), and Raman spectroscopy. The results showed that the obtained ZnO NWs have diameters in the range of 300-350 nm with lengths of several tens micrometers. The prepared ZnO NWs are of a single crystal, which have a hexagonal wurtzite crystal structure with c-axis (002) orientation growth perpendicular to the substrate surface. The NW arrays had a good crystal quality with excellent optical properties, indicating a sharp and strong ultraviolet emission at 380 nm, and a weak visible emission at around 516 nm.

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Fabrication of graphene layers from multiwalled carbon nanotubes using high dc pulse

Cited by 41 publications

References 19 publications

Facile synthesis of high-quality graphene nanoribbons

Facile synthesis of high-quality graphene nanoribbons

Sculpting molecular structures from bilayer graphene and other materials

CATALYST–FREE GROWTH OF WELL–ALIGNED ZnO NANOWIRES ON GRAPHENE/Si SUBSTRATEBY THERMAL EVAPORATION

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