AVS 52nd International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS+TF-ThA

Paper PS+TF-ThA8
Synthesis of Aligned Carbon Nanotubes by RF-Plasma-Assisted DC Plasma Chemical Vapor Deposition

Thursday, November 3, 2005, 4:20 pm, Room 302

Session: Emerging Plasma Applications
Presenter: Y. Hayashi, Kyoto Institute of Technology, Japan
Authors: Y. Hayashi, Kyoto Institute of Technology, Japan
T. Fukumura, Kyoto Institute of Technology, Japan
R. Utsunomiya, Nissin Electric Co. Ltd., Japan
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Aligned carbon nanotubes (CNTs) grown on a substrate are expected to be applied to the electron emitters of a field emission display. Plasma-enhanced chemical vapor deposition (plasma CVD) enables highly aligned growth of multi-walled CNTs by drawing them toward plasma in the sheath electric field.@footnote 1@ However the problem of aligned CNT growth by plasma CVD is large-area growth. We have developed a new method of large-area growth of CNTs under stable DC plasma sustainment without arcing by the assistance of RF plasma. Plates of RF electrode, a grounded electrode, and DC cathode were placed parallel in this order in a vacuum chamber. The grounded electrode was gridded so as to pass a part of the RF generated plasma into the space of DC discharge. Iron substrates were placed on the cathode electrode. 13.56 MHz RF power of 500 W was induced to the RF electrode and negative bias of 325 V was induced to the cathode electrode. 20 % methane diluted in hydrogen was introduced into the chamber with the operating pressure of 1000 Pa during the growth of CNTs. Well-aligned carbon fibers were observed by scanning electron microscopy and about 50 concentric layers of graphite with hollows were observed by transmission electron microscopy. These results confirm that CNTs can be synthesized by this method. DC discharge current was 0.7 A at the discharge voltage of 325 V under the assistance of 500 W RF-plasma, while it was 0.57 A without RF-plasma. The decrease of discharge impedance caused the stable sustainment of DC glow discharge without arcing. It is concluded that the large-area growth of well-aligned CNTs under the stable sustainment of DC glow discharge can be carried out by RF-Plasma-Assisted DC Plasma CVD. @FootnoteText@ @footnote 1@Y. Hayashi, T. Negishi and S. Nishino, J. Vac. Sci. Technol. A19, 1796(2001).