Browsing by Author "Peng, YR"

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Effects of buffer layer materials and process conditions on growth mechanisms of forming networks of SWNTs by microwave plasma chemical vapor deposition
(2005-11-01)
Wang, WH
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Peng, YR
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Kuo, CT
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材料科學與工程學系
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Department of Materials Science and Engineering
This study investigates the growth mechanism of 1C compatible processes and to the feasibility of synthesizing networks of single-walled carbon nanotubes (SWNT-) at lower temperatures (similar to 610 degrees C) on Si wafer using microwave plasma chemical vapor deposition (MPCVD) with CH4 and H-2 as source gases. The effects of the buffer layer materials (ZnS-SiO2, Al2O3, AlON, and AlN) and process conditions on growth of carbon nanostructures with Co as catalyst were also examined, where the buffer layers and Co catalyst were deposited in sequence by physical vapor deposition (PVD), followed by H-plasma pretreatment before deposition of carbon nanostructures. Additionally, the morphologies and bonding structures of carbon nanostructures were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and Raman Spectroscopy. Analytical results demonstrate that networks of SIANTs are more favorable to be synthesized by selecting proper buffer layer material (e.g., AION), and under higher temperatures, thinner catalyst thickness (e.g., 5 run) and lower CH4/H-2 ratio (e.g., 5/100 sccm/sccm). The networks of SWNTs can be fabricated at temperatures as low as similar to 610 degrees C by manipulating these parameters. In conclusion, the growth mechanism determines the conditions for the formation of nano-sized extrusions on catalyst particles surface. (c) 2005 Elsevier B.V. All rights reserved.
Template-assisted synthesis of mesoporous tubular carbon nanostructure by chemical vapor infiltration method
(2006-03-01)
Lo, AY
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Huang, SJ
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Chen, WH
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Peng, YR
;
Kuo, CT
A novel synthesis route for fabrication of tubule mesoporous carbon by chemical vapor infiltration method using a mesoporous silica template is reported. Powder X-ray diffraction and pore size analysis revealed that the nano-sized carbon material consists of three-dimensional framework structure and possesses a bimodal pore distribution with average pore diameters of 1.5 and 3.3 nm. The formation of the former pore is ascribed due to removal of the silica template, whereas the latter represents pore size of tubule carbon with ordered structure having an average wall thickness corresponding to about 1.3 layers of graphitic sheets, as verified by Raman spectroscopy and electron microscopy. (c) 2005 Published by Elsevier B.V.