IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Nanotubes: Science and Applications Topical Conference Tuesday Sessions
       Session NT+EL+NS-TuM

Paper NT+EL+NS-TuM4
Large-Area Growth of Well-Aligned Carbon Nanotubes by Hot-Filament-Assisted DC Plasma Chemical Vapor Deposition

Tuesday, October 30, 2001, 9:20 am, Room 133

Session: Nanotubes: Growth and Characterization
Presenter: T. Negishi, Kyoto Institute of Technology, Japan
Authors: T. Negishi, Kyoto Institute of Technology, Japan
Y. Hayashi, Kyoto Institute of Technology, Japan
S. Nishino, Kyoto Institute of Technology, Japan
Correspondent: Click to Email
For the realization of field emission displays (FED) using carbon nanotubes (CNT), the efficient production method of CNT suitable for them should be developed. In order to obtain aligned CNT perpendicular to substrates for the application, direct growth on catalyst metal plates is desirable. It was reported that well-aligned carbon nanotubes were grown by plasma chemical vapor deposition (CVD). However the growth area was less than 1 inch in diameter. We have succeeded in carrying out the growth of well-aligned CNT with high density on a 5 cm x 5 cm nickel plate by hot-filament-assisted DC plasma (HF-DCP) CVD in the gas of CH@sub 4@/H@sub 2@. The growth method and conditions were as follow. DC voltage of -500V was impressed on the substrate with hot-filaments grounded. The filaments not only raise the temperature of a substrate, but stabilize a DC plasma. A luminous region was observed just above the substrate. By the optical emission spectroscopy, it was confirmed that the luminescence was derived from exited hydrogen and hydrocarbon radicals. Therefore the process is called HF-DCP CVD. Nickel substrates were heated by the filaments to 450-600 °C. The substrates were pretreated in pure hydrogen plasma before the growth of carbon nanotubes. Well-algined CNT about 50 nm in diameter and about 10 microns in length were observed by scanning electron microscopy in the density of about 10@super 9@ cm@super -2@ on the surface of the treated substrate. Field-emission properties of CNT were evaluated and a current density of 1.2 mA/cm@super 2@ was obtained for -1500V bias between the substrate and the counter electrode with a distance of 300 um. By this method, the growth of well-aligned CNT in an even larger area is expected.