scholarly journals Growth Mechanism of a Hybrid Structure Consisting of a Graphite Layer on Top of Vertical Carbon Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Nicolo' Chiodarelli ◽  
Cigang Xu ◽  
Olivier Richard ◽  
Hugo Bender ◽  
Alexander Klekachev ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Growth Conditions ◽  
Hybrid Structure ◽  
Carbon Layer ◽  
Time Dynamic ◽  
Catalyst Film ◽  
Optical And Electronic Properties ◽  
Deposition Processes

Graphene and carbon nanotubes (CNTs) are both carbon-based materials with remarkable optical and electronic properties which, among others, may find applications as transparent electrodes or as interconnects in microchips, respectively. This work reports on the formation of a hybrid structure composed of a graphitic carbon layer on top of vertical CNT in a single deposition process. The mechanism of deposition is explained according to the thickness of catalyst used and the atypical growth conditions. Key factors dictating the hybrid growth are the film thickness and the time dynamic through which the catalyst film dewets and transforms into nanoparticles. The results support the similarities between chemical vapor deposition processes for graphene, graphite, and CNT.

Carbon nanotubes grown on different-sized rectangular patterns

2004 ◽  
Vol 19 (6) ◽  
pp. 1803-1807 ◽  
Author(s):  
Lujun Pan ◽  
Yoshikazu Nakayama ◽  
Hideki Shiozaki ◽  
Chikashi Inazumi
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Line Width ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Surface Shape ◽  
Iron Film ◽  
Nucleation Process ◽  
Catalyst Film ◽  
Field Emission Displays

Carbon nanotubes have been synthesized by chemical vapor deposition using a thin iron film as catalyst on the silicon substrate with different-sized rectangular patterns. It is found that the carbon nanotubes grow vertically to the substrate in a high density with a surface shape similar to that of the substrate when the line width of the patterns are larger than 1 μm, However, when the line width of the pattern is reduced to below 0.5 μm, carbon nanotubes cannot grow vertically anymore. This phenomenon might be caused by the relaxation of stress in catalyst film and the coalescence of the catalyst clusters to form particles or grains, which contributes to the migration of catalyst from edge to inner part during the nucleation process. These results are very useful for the fabrication of field-emission displays and other devices using patterned carbon nanotubes.

Fabrication and electrochemical characterization of super-capacitor based on three-dimensional composite structure of graphene and a vertical array of carbon nanotubes

2018 ◽  
Vol 52 (22) ◽  
pp. 3039-3044 ◽  
Author(s):  
Daniel Choi ◽  
Eui-Hyeok Yang ◽  
Waqas Gill ◽  
Aaron Berndt ◽  
Jung-Rae Park ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Deposition ◽  
Composite Structure ◽  
Graphene Layer ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Vertical Array ◽  
Pressure Chemical

We have demonstrated a three-dimensional composite structure of graphene and carbon nanotubes as electrodes for super-capacitors. The goal of this study is to fabricate and test the vertically grown carbon nanotubes on the graphene layer acting as a spacer to avoid self-aggregation of the graphene layers while realizing high active surface area for high energy density, specific capacitance, and power density. A vertical array of carbon nanotubes on silicon substrates was grown by a low-pressure chemical vapor deposition process using anodized aluminum oxide nanoporous template fabricated on silicon substrates. Subsequently, a graphene layer was grown by another low-pressure chemical vapor deposition process on top of a vertical array of carbon nanotubes. The Raman spectra confirmed the successful growth of carbon nanotubes followed by the growth of high-quality graphene. The average measured capacitance of the three-dimensional composite structure of graphene-carbon nanotube was 780 µFcm−2 at 100 mVs−1.

Variation of Size and Alignment in Carbon Nanotubes by Changes of Growth Condition

2001 ◽  
Vol 7 (S2) ◽  
pp. 428-429
Author(s):  
Paula P. Provencio ◽  
Michael P. Siegal ◽  
Donald L. Overmyer
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Dwell Time ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Nitrogen Atmosphere ◽  
Ni Catalyst ◽  
Multiwall Carbon Nanotube ◽  
Catalyst Layers

Carbon nanotubes have previously been grown on Ni coated glass, aligned vertical to the substrate over a multi-centimeter square area1. Under vacuum, the aligned nanotubes were grown below 666° C (strain point of the best display glass) by plasma-enhanced hot filament, chemical vapor deposition. It was found, the size and alignment of the nanotubes could be varied by changing the dwell time and the thickness of the catalytic Ni layer by plasma etching. in more recent, ongoing studies, the size of carbon nanotubes is varied by changing the growth temperature and dwell time under acetylene/nitrogen atmosphere using chemical vapor deposition onto W and Ni coated Si.Multiwall carbon nanotube films are grown using a thermally-activated chemical vapor deposition process. Thin Ni catalyst layers are sputtered onto W-coated Si(100) and reduced in a 600°C CO anneal. Nanotubes then grow at temperatures ranging from 630 - 790°C in an acetylene/nitrogen mixture.

The Effect of Inoculum in the Preparation of Fermented Tapioca for Nanotechnology Applications Based on FT-IR Studies

2013 ◽  
Vol 667 ◽  
pp. 534-537
Author(s):  
M.Z. Nuraini ◽  
S. Aishah ◽  
S.F. Nik ◽  
Mohamad Rusop
Keyword(s):  
Carbon Nanotubes ◽  
Gas Flow ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ir Studies ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes ◽  
Ft Ir Spectroscopy

Fermented tapioca which is a new starting material was used as a carbon precursor. Carbon nanotubes (CNTs) were deposited on silicon wafer (Si) by Thermal Chemical Vapor Deposition (TCVD). The gas flow of Argon (Ar) was constant at 70 bubbles per minute and 20 minutes of deposition time. Before the deposition process, silicon was coated with Nickel using spin coater. Various parameters such as amount of inoculums have been studied. Chemical functional groups of carbon nanotubes were characterized using FT-IR Spectroscopy. The FT-IR result shows peaks attributed to multi–walled carbon nanotubes (MWCNT) vibration modes.

In Situ Filling of Fe/Ni Oxide Nanowire into Carbon Nanotubes Doped with Nitrogen in CH4/H2/Air Plasma

2011 ◽  
Vol 15 ◽  
pp. 51-56 ◽  
Author(s):  
Xin Wang ◽  
Ya Yu Wang ◽  
Wei Tao Zheng ◽  
Zan Wang
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor ◽  
Air Plasma ◽  
Catalyst Film ◽  
Metal Oxide Nanoparticle ◽  
Transmission Electron ◽  
Nitrogen Doped Carbon ◽  
Ni Oxide

Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized using air as the nitrogen carrier gas and CH4 as the carbon source by plasma-enhanced chemical vapor deposition over a thin catalyst film of Fe50Ni50. Transmission electron microscopy and high resolution transmission electron microscopy measurements have indicated that the N-CNTs grew with a tip-type growth mode. When H2 was added to the CH4/air plasmas during the N-CNTs growth stage, it was found that Fe/Ni oxide nanowire was filled into the nanotube. However, without adding H2 in the CH4/air mixture plasma, only metal oxide nanoparticle was found on the tip of the N-CNT.

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