Elongation of arrays of amorphous carbon tubes

Wang, Lung Shen; Wang, Chia Hsin; Peng, Chih Wei; Lee, Chi Young; Chiu, Hsin‐Tien

doi:10.1016/j.carbon.2005.04.027

Cited by 24 publications

(4 citation statements)

References 6 publications

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“…In Figure F, Raman spectra of an as-grown CNC sample before and after the annealing are shown. The as-grown sample reveals two relatively broad and overlapping peaks at 1345 and 1588 cm −1 , assigned to the D band and the G band of carbon materials, respectively . Shapes of the peaks suggest that the as-grown CNCs are composed of disordered carbon with a low degree of graphitization.…”

Section: Resultsmentioning

confidence: 96%

“…The as-grown sample reveals two relatively broad and overlapping peaks at 1345 and 1588 cm Ϫ1 , assigned to the D band and the G band of carbon materials, respectively. 32 Shapes of the peaks suggest that the as-grown CNCs are composed of disordered carbon with a low degree of graphitization. On the other hand, the annealed sample shows its D and G band peaks at 1337 and 1583 cm Ϫ1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

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Growth of Carbon Nanocoils from K and Ag Cooperative Bicatalyst Assisted Thermal Decomposition of Acetylene

et al. 2010

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Growth of amorphous carbon nanocoil (CNC) from acetylene on Si substrates was achieved by using nanosized Ag and K as the catalysts. The deposition of CNC was carried out inside a hot-wall reactor at 723 K using H2 as the carrier gas. Based on the observed results, we propose a cooperative bimetal catalyst enhanced vapor-liquid-solid (VLS) growth mechanism to rationalize the CNC growth. In the reaction, the liquid phase metallic K dehydrogenated acetylene into the solid-state carbon, while the Ag nanoparticle assisted the extension of carbon one-dimensionally (1-D) via a tip-growth mechanism. Due to the adhesive force between the K liquid and the carbon, the 1-D solid curled along the C-K interface into the nanocoil shape. Some CNC samples were further heat-treated at 1423 K and showed very good field emission properties. They emitted electrons (10 microA/cm2) at a turn-on field Eto of 2.51 V/microm, while Jmax reached 17.71 mA/cm2 at 5.64 V/microm. The field enhancement factor beta was calculated to be 2124, comparable to other carbon nanotube (CNT) and CNC based emitters. The CNC was also characterized by using the electrochemical behavior of K3[Fe(CN)6] via cyclic voltammetry (CV). The electrochemical surface area of a CNC electrode (geometric surface area 0.078 cm2) was calculated to be 0.143 cm2. These properties suggest that the CNC electrodes may have potential applications in field emission and electrochemical devices.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Growth of Carbon Nanocoils from K and Ag Cooperative Bicatalyst Assisted Thermal Decomposition of Acetylene

et al. 2010

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“…However, microporous carbons can be used in additional ways if their irregular pores are properly optimized. − For aqueous EDLCs, the <1 nm pores have been reported to be linked to an anomalous increase in specific capacitance. − In principle, >0.5 nm micropores could be electrochemically available for aqueous electrolytes. , Xu et al recently synthesized ultramicroporous carbons with a regular pore size of 0.55 nm by using poly(vinylidene fluoride) as the carbon source, and the carbons as a supercapacitor electrode have a gravimetric capacitance of 194 F g –1 at 1.0 A g –1 in a KOH electrolyte . Besides, the carbon electrode is suitable for charge–discharge operation at a large current density of 10 A g –1 coupled with a specific capacitance of 145 F g –1 , indicating good electrochemical performance.…”

Section: Introductionmentioning

confidence: 99%

Ultramicroporous Carbon Nanoparticles for the High-Performance Electrical Double-Layer Capacitor Electrode

et al. 2014

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Novel ultramicroporous carbon nanoparticles (UCNs) are synthesized on the basis of solvothermal polymerization of phloroglucinol and terephthaldehyde in dioxane at 220 °C, followed by carbonization at 850 °C. The resultant UCNs show regular 0.54 nm ultramicropores and particle sizes of ∼30 nm. The UCNs as electrode materials for electrical double-layer capacitors (EDLCs) show a specific capacitance of 206 F g −1 at 1.0 A g −1 in a 6 M KOH aqueous solution. The UCN electrode is suitable for charge−discharge operation even at a very high current density of 50 A g −1 coupled with a capacitance of 135 F g −1 , indicating excellent high-rate electrochemical performance. The electrochemical capacitance of the UCN electrode has a high retention of 97.6% after 5000 cycles at 1.0 A g −1 tested by a standard three-electrode system (97.3% for the two-electrode cell), which implies a good electrochemical cycling life. This study highlights promising prospects of novel UCNs as advanced electrode materials for EDLCs where a high level of current charge and discharge is required.

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“…Similarly, Yang et al [19] have deposited diamond thin film by graphite etching through hydrogen as carbon source in HFCVD reactor without plasma discharge. Moreover, high quality diamond films have also been deposited at temperatures as low as 250 • C using microwave plasma reactor [20]. Dependence of the concentration of atomic hydrogen on the pressure in a region between 7 and 73 mbar was investigated via REMPI by Smith et al [21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Reactor Pressure on Electrical and Structural Properties of Diamond Films Grown by Hot-Filament CVD

2017

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Polycrystalline diamond films with preferred (111) and (222) facets were fabricated inside hot filament chemical vapour deposition reactor on silicon wafers using a mixture of 1% methane in hydrogen at various reactor pressures ranging from 10 to 50 mbar. Regarding characterization of diamond films, internal texture, surface morphology, quality of diamond and electrical conductivity were investigated using X-ray diffraction, scanning electron microscopy, the Raman spectroscopy and four-point-probe van der Pauw techniques, respectively. Results of these studies demonstrate that polycrystalline diamond structure is grown in random orientation with (111) facet being dominant showing sharp grain boundaries. Moreover, growth rate was found to increase with pressure up to 20 mbar and then decreased for further rise in pressure. That is why grain density is high with relatively smaller grains at higher pressures caused by higher nucleation rates. In contrast, electrical resistivity decreased ≈ 3 orders of magnitude showing a minimum at 2.9 × 10 6 Ω cm as pressure was increased in the reactor. Reactor pressure during film growth resulted in poor surface morphology, absence of sp 3 bonds and low resistivity. Hence, decrease of resistivity makes diamond films desirable for many electrical applications in semiconducting/electronic devices.

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Elongation of arrays of amorphous carbon tubes

Cited by 24 publications

References 6 publications

Growth of Carbon Nanocoils from K and Ag Cooperative Bicatalyst Assisted Thermal Decomposition of Acetylene

Growth of Carbon Nanocoils from K and Ag Cooperative Bicatalyst Assisted Thermal Decomposition of Acetylene

Ultramicroporous Carbon Nanoparticles for the High-Performance Electrical Double-Layer Capacitor Electrode

Effect of Reactor Pressure on Electrical and Structural Properties of Diamond Films Grown by Hot-Filament CVD

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