scholarly journals Hydrogen Plasma Treatment of Aligned Multi-Walled Carbon Nanotube Arrays for Improvement of Field Emission Properties

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4420
Author(s):  
Dmitriy V. Gorodetskiy ◽  
Artem V. Gusel’nikov ◽  
Alexander G. Kurenya ◽  
Dmitry A. Smirnov ◽  
Lyubov G. Bulusheva ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Plasma Treatment ◽  
Low Voltage ◽  
Hydrogen Plasma ◽  
Etching Rate ◽  
Chemical Vapor ◽  
Field Emission Properties ◽  
Before And After ◽  
Cnt Arrays ◽  
Emission Threshold

Vertically aligned carbon nanotube (CNT) arrays show potential for the development of planar low-voltage emission cathodes. The characteristics of cathodes can be improved by modifying their surface, e.g., by hydrogen plasma treatment, as was performed in this work. The surface of multi-walled CNT arrays grown on silicon substrates from toluene and ferrocene using catalytic chemical vapor deposition was treated in a high-pressure (~104 Pa) microwave reactor. The structure, composition, and current-voltage characteristics of the arrays were studied before and after hydrogen plasma treatment at various power values and durations. CNT tips were destroyed and catalytic iron was released from the CNT channels. The etching rate was influenced by iron particles that formed on the array surface. The lower emission threshold in the plasma-treated arrays than in the initial sample is explained by the amplification factor of the local electric field increasing due to graphene structures of unfolded nanotube layers that formed at the CNT tips.

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.

Electrical Properties of Thin Film and Bulk Diamond Treated in Hydrogen Plasma

1989 ◽  
Vol 162 ◽  
Author(s):  
Sacharia Albin ◽  
Linwood Watkins
Keyword(s):  
Natural Diamond ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Free Standing ◽  
Before And After ◽  
Type Ia ◽  
Bulk Diamond

ABSTRACTCurrent-voltage characteristics of type Ia synthetic diamond, type IIb natural diamond and free-standing diamond films were measured before and after hydrogenation. The diamond films were polycrystalline, deposited on sacrificial silicon substrates using a microwave chemical vapor deposition process. On hydrogenation, all the samples showed several orders of magnitude increase in conductivity. Hydrogenation was carried out under controlled conditions to study the changes in the I-V characteristics of the samples. The concentration of electrically active hydrogen was determined from the I-V data. Hydrogen passivation of deep traps in diamond is clearly demonstrated.

Improvement of Field-Emission Properties of Screen Printed Carbon Nanotube Films via Argon Plasma Treatment

2006 ◽  
Vol 153 (6) ◽  
pp. H111
Author(s):  
Jung-Ah Lee ◽  
Jin-Woo Lee ◽  
Dae-Sung Yoon ◽  
Kyeong-Kap Paek ◽  
Yun-Hi Lee ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Plasma Treatment ◽  
Field Emission ◽  
Argon Plasma ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Screen Printed ◽  
Nanotube Films

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.

Enhanced Wettability of Nanocrystalline Diamond Films for Biocoating Applications

2012 ◽  
Vol 1395 ◽  
Author(s):  
Jason H. C. Yang ◽  
Kungen Teii
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Film Surface ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Polar Component ◽  
Oxygen Plasma Treatment

ABSTRACTNanocrystalline diamond (NCD) films are prepared from Ar-rich/N2/CH4 and Ar-rich/H2/CH4 mixtures by microwave plasma-enhanced chemical vapor deposition, and further treated by microwave hydrogen and oxygen plasma exposures separately to enhance the wetting property. The hydrogen plasma treatment has small effect on the surface roughness, while the oxygen plasma treatment forms fine protrusions on the film surface. Results show that the wettability of the hydrogen plasma treated NCD film is nearly constant or little improvement as the polar component of the apparent surface free energy is close to the as-deposit NCD film. In contrast, the wettability of the oxygen plasma treated NCD film is improved dramatically such that the contact angle is reduced from 92º and 4.7º to almost 0º for water and 1-bromonaphthalene, respectively, and the polar component increases significantly to 34 mJ/m2. The low contact angle suggests that the film is considerably a cell adhesive friendly surface, which is essential in maintaining multicellular structure, and thus making it a favorable wetting surface for biological and biomedical applications.

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.

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