scholarly journals Feedstock Diffusion and Decomposition in Aligned Carbon Nanotube Arrays

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Rong Xiang ◽  
Erik Einarsson ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Carbon Nanotube ◽  
Carbon Source ◽  
Flow Rate ◽  
Chemical Vapor ◽  
Mean Free Path ◽  
Diffusion Limit ◽  
Diffusion Resistance ◽  
Multiwalled Carbon ◽  
Cnt Arrays ◽  
Growth Deceleration

Feedstock diffusion and decomposition in the root growth of aligned carbon nanotube (CNT) arrays is discussed. A nondimensional modulus is proposed to differentiate catalyst poisoning controlled growth deceleration from one which is diffusion controlled. It is found that, at present, aligned multiwalled carbon nanotube (MWNT) arrays are usually free of feedstock diffusion resistance. However, for single-walled carbon nanotube (SWNT) arrays, since the intertube distance is much smaller than the mean free path of carbon source (ethanol here), high diffusion resistance in some currently available samples is significantly limiting the growth rate. The method presented here is also able to predict the critical lengths in different chemical vapor deposition (CVD) processes from which CNT arrays begin to meet this diffusion limit, as well as the possible solutions to this diffusion caused growth deceleration. The diffusion of carbon source inside of an array becomes more important when we found ethanol undergoes severe thermal decomposition at the reaction temperature. This means, in a typical alcohol CVD, hydrocarbons and radicals decomposed from ethanol may collide and react with the outer walls of SWNTs before reaching catalyst particles. When flow rate is low and ethanol is thoroughly decomposed, the produced SWNTs contain more soot structures than the SWNTs obtained at higher ethanol flow rate. Understanding the mass transport and reaction inside a SWNT array is helpful to synthesize longer and cleaner SWNTs.

scholarly journals Feedstock Diffusion and Decomposition in Aligned Carbon Nanotube Arrays

2009 ◽  
Author(s):  
Rong Xiang ◽  
Erik Einarsson ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Carbon Nanotube ◽  
Carbon Source ◽  
Flow Rate ◽  
Chemical Vapor ◽  
Mean Free Path ◽  
Diffusion Limit ◽  
Diffusion Resistance ◽  
Diffusion Controlled ◽  
Cnt Arrays ◽  
Growth Deceleration

Feedstock diffusion and decomposition in the root growth of aligned carbon nanotube (CNT) arrays is discussed. A non-dimensional modulus is proposed to differentiate catalyst-poisoning controlled growth deceleration from one which is diffusion controlled. It is found that, at current stage, aligned multi-walled carbon nanotube (MWNT) arrays are usually free of feedstock diffusion resistance. However, for single-walled carbon nanotube (SWNT) arrays, since the inter-tube distance is much smaller than the mean free path of carbon source (ethanol here), high diffusion resistance is significantly limiting the growth rate. The method presented here is also able to predict the critical lengths in different chemical vapor deposition (CVD) processes from which CNT arrays begin to meet this diffusion limit, as well as the possible solutions to this diffusion caused growth deceleration. The diffusion of carbon source inside of an array becomes more important when we found ethanol undergoes severe thermal decomposition at the reaction temperature. This means, in a typical alochol CVD, hydrocarbons and radicals decomposed from ethanol may collide and react with the outer walls of SWNTs before reaching catalyst particles. We found when flow rate is low and ethanol is thoroughly decomposed, the produced SWNTs contain more soot structures than the SWNTs obtained at higher ethanol flow rate. Understanding the mass transport and reaction inside a SWNT array is helpful to synthesize longer and cleaner SWNTs.

scholarly journals Synthesis of High-Quality Carbon Nanotube Arrays without the Assistance of Water

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Yongfeng Luo ◽  
Xinjun Wang ◽  
Mengdong He ◽  
Xi Li ◽  
Hong Chen
Keyword(s):  
Carbon Nanotube ◽  
Carbon Source ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Nanotube Arrays ◽  
High Quality ◽  
Nanotube Array ◽  
Carbon Nanotube Arrays ◽  
Cnt Arrays ◽  
First Time

Long and high-quality carbon nanotube (CNT) arrays have been synthesized through a chemical vapor deposition process. The Fe/Al2O3on silicon was used as the catalyst, ethylene as the carbon source, and a gas mixture of Ar and H2gases as the carrying gas. It is found for the first time that the high-quality and superlong carbon nanotube array can be improved by varying the content of hydrogen and carbon source.

Highly Organized Carbon Nanotube-PDMS Hybrid System for Multifunctional Flexible Devices

2007 ◽  
Author(s):  
Yung J. Jung ◽  
Laila Jaber-Ansari ◽  
Xugang Xiong ◽  
Sinan Mu¨ftu¨ ◽  
Ahmed Busnaina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Fields ◽  
Composite Structures ◽  
Field Enhancement ◽  
Chemical Vapor ◽  
Casting Process ◽  
Dip Coating ◽  
Network Architectures ◽  
Multiwalled Carbon

We will present a method to fabricate a new class of hybrid composite structures based on highly organized multiwalled carbon nanotube (MWNT) and singlewalled carbon nanotube (SWNT) network architectures and a polydimethylsiloxane (PDMS) matrix for the prototype high performance flexible systems which could be used for many daily-use applications. To build 1–3 dimensional highly organized network architectures with carbon nanotubes (both MWNT and SWNT) in macro/micro/nanoscale we used various nanotube assembly processes such as selective growth of carbon nanotubes using chemical vapor deposition (CVD) and self-assembly of nanotubes on the patterned trenches through solution evaporation with dip coating. Then these vertically or horizontally aligned and assembled nanotube architectures and networks are transferred in PDMS matrix using casting process thereby creating highly organized carbon nanotube based flexible composite structures. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We will demonstrate its robustness under large stress conditions, under which the composite is found to retain its conducting nature. We will also demonstrate that these structures can be directly utilized as flexible field-emission devices. Our devices show some of the best field enhancement factors and turn-on electric fields reported so far.

Carbon nanotube cathodes covered on the cylindrical surface of a fiber

RSC Advances ◽  
2015 ◽  
Vol 5 (22) ◽  
pp. 17049-17053 ◽  
Author(s):  
Xianqi Wei ◽  
Youzhang Zhu ◽  
Xianjun Xia ◽  
Xiaoli Wang ◽  
Weihuan Liu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Field Emission ◽  
Vapor Deposition ◽  
Cylindrical Surface ◽  
Chemical Vapor ◽  
Quartz Optical Fiber ◽  
Cnt Arrays ◽  
Field Emission Cathodes ◽  
Waveguide Surface

Carbon nanotube (CNT) arrays were synthesized on the cylindrical waveguide surface of a quartz optical fiber by chemical vapor deposition (CVD) to serve as field emission cathodes.

Reactor Scale Model of Multiwalled Carbon Nanotube Growth in a Tube Flow Chemical Vapor Deposition Reactor

2009 ◽  
Author(s):  
Jeffrey J. Lombardo ◽  
Wilson K. S. Chiu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotubes ◽  
Computational Models ◽  
Chemical Vapor ◽  
Scale Model ◽  
Tube Flow ◽  
Multiwalled Carbon ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

Even though a large number of applications for multiwalled carbon nanotubes have been proposed, there is relatively limited knowledge about the optimal conditions in which to create multiwalled carbon nanotubes (MWNTs). Computational models have been shown to be a promising tool to determine the best carbon nanotube growth conditions. In this paper the growth of MWNTs in a tube flow CVD reactor was studied through the use of the commercial software package COMSOL, where details steps have been described to reformulate an existing single walled carbon nanotube (SWNT) growth model to accommodate MWNTs followed by validation and growth rate prediction. Higher growth rates were predicted for MWNTs than SWNTs which is a result of the increase in pathways for carbon to form carbon nanotubes based on the additional walls. Results indicate that selecting the correct number of walls can be important to the results of the model.

Compound growth and microstructure of carbon nanotube

2003 ◽  
Vol 18 (10) ◽  
pp. 2459-2463 ◽  
Author(s):  
Zaoli Zhang ◽  
Lian Ouyang ◽  
Zujin Shi ◽  
Zhennan Gu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Nanotube ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Multiwalled Carbon ◽  
Catalyst Nanoparticles ◽  
Single Walled Carbon Nanotube ◽  
Fe Catalyst ◽  
Transmission Electron

The compound growth of single-walled carbon nanotube (SWCNT) and multiwalled carbon nanotube (MWCNT), which formed a nanotube cable, was achieved by the chemical vapor deposition of natural gas on an Fe catalyst supported on SiO2–Al2O3 hybrid materials at 950 °C. The microstructure of nanotubes was characterized by high-resolution transmission electron microscopy (HRTEM). The SWCNTs encapsulated inside MWCNTs can be two, three, or even more in quantity with a diameter range from 1.0 nm to 2.0 nm. The diameter of SWCNT is controlled by the size of the catalyst nanoparticles. Some bundles of SWCNT and double-walled nanotubes were also found. The possible mechanism of compound growth is briefly discussed.

Recent Research Progress of Carbon Nanotube Arrays Prepared by Plasma Enhanced Chemical Vapor Deposition Method

2016 ◽  
Vol 852 ◽  
pp. 308-314
Author(s):  
Er Xiong Ding ◽  
Hong Zhang Geng ◽  
Li He Mao ◽  
Wen Yi Wang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Research Progress ◽  
Chemical Vapor Deposition Method ◽  
In Situ Fabrication ◽  
Microwave Pecvd ◽  
Cnt Arrays ◽  
The Moment

Preparing carbon nanotube (CNT) arrays by plasma enhanced chemical vapor deposition (PECVD) method can dramatically reduce the deposition temperature, which makes it possible for in-situ fabrication of CNT-based nanoelectronic devices. In this paper, up to date research progress of CNT arrays prepared by PECVD method was presented, including radio frequency PECVD, direct current PECVD and microwave PECVD. Then, morphology and quality of CNT arrays were compared. In the end, we analyzed the possible challenges encountered through CNT array preparation by PECVD method at the moment and in the future.

Preparation and Characterization of Aligned Carbon Nanotube Fibers

2013 ◽  
Vol 275-277 ◽  
pp. 1794-1797
Author(s):  
Yong Feng Luo ◽  
Cui Zhou ◽  
Xi Li ◽  
Shui Li ◽  
Zhong Zhi Sheng
Keyword(s):  
Carbon Nanotube ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
High Quality ◽  
Dry Spinning ◽  
Excellent Mechanical Property ◽  
Cnt Arrays ◽  
Carbon Nanotube Fibers

High-quality carbon nanotube (CNT) arrays have been synthesized through a chemical vapor deposition process. The Fe/Al2O3 on silicon was used as the catalyst, ethylene as the carbon source, and a mixture gas of Ar and H2 gases as the carrying gas. With spinnable CNT arrary as initial materials, aligned carbon nanotube fibers were continuously fabricated by dry spinning. And then we study the excellent mechanical property of the carbon nanotube fibers.

Carbon Nanotube Array Thermal Interfaces on Chemical Vapor Deposited Diamond

2007 ◽  
Author(s):  
Baratunde A. Cola ◽  
Xianfan Xu ◽  
Timothy S. Fisher
Keyword(s):  
Carbon Nanotube ◽  
Diamond Film ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Photoacoustic Technique ◽  
Nanotube Array ◽  
Carbon Nanotube Array ◽  
Chemical Vapor Deposited ◽  
Cnt Arrays ◽  
Film Interface

Carbon nanotube (CNT) arrays have been directly synthesized on plasma-enhanced chemical vapor deposited diamond films in the same growth chamber. The diamond films were grown using a bias-enhanced nucleation technique that produces relatively smooth and flat films. The thermal resistances of the CNT array/diamond film interface were measured using a photoacoustic technique to be approximately 12 mm2·K/W at moderate pressures.

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