title: High Stability Electron Field Emitters Synthesized via the Combination of Carbon Nanotubes and N₂-Plasma Grown Ultrananocrystalline Diamond Films.
abstract: An electron field emitter with superior electron field emission (EFE) properties and improved lifetime stability is being demonstrated via the combination of carbon nanotubes and the CH4/N2 plasma grown ultrananocrystalline diamond (N-UNCD) films. The resistance of the carbon nanotubes to plasma ion bombardment is improved by the formation of carbon nanocones on the side walls of the carbon nanotubes, thus forming strengthened carbon nanotubes (s-CNTs). The N-UNCD films can thus be grown on s-CNTs, forming N-UNCD/s-CNTs carbon nanocomposite materials. The N-UNCD/s-CNTs films possess good conductivity of σ = 237 S/cm and marvelous EFE properties, such as low turn-on field of (E0) = 3.58 V/μm with large EFE current density of (J(e)) = 1.86 mA/cm(2) at an applied field of 6.0 V/μm. Moreover, the EFE emitters can be operated under 0.19 mA/cm(2) for more than 350 min without showing any sign of degradation. Such a superior EFE property along with high robustness characteristic of these combination of materials are not attainable with neither N-UNCD films nor s-CNTs films alone. Transmission electron microscopic investigations indicated that the N-UNCD films contain needle-like diamond grains encased in a few layers of nanographitic phase, which enhanced markedly the transport of electrons in the N-UNCD films. Moreover, the needle-like diamond grains were nucleated from the s-CNTs without the necessity of forming the interlayer that facilitate the transport of electrons crossing the diamond-to-Si interface. Both these factors contributed to the enhanced EFE behavior of the N-UNCD/s-CNTs films.
authors.affiliation: Department of Materials Science and Engineering, National Tsing-Hua University , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Ting-Hsun
authors.initials: TH
authors.lastname: Chang
authors.affiliation: Department of Materials Science and Engineering, National Tsing-Hua University , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Ping-Yen
authors.initials: PY
authors.lastname: Hsieh
authors.affiliation: Department of Engineering and System Science, National Tsing-Hua University , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Srinivasu
authors.initials: S
authors.lastname: Kunuku
authors.affiliation: Center for Measurement Standards, Industrial Technology Research Institute , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Shiu-Cheng
authors.initials: SC
authors.lastname: Lou
authors.affiliation: Department of Physics, Tamkang University , New Taipei City 251, Taiwan, R.O.C.
authors.forename: Divinah
authors.initials: D
authors.lastname: Manoharan
authors.affiliation: Department of Engineering and System Science, National Tsing-Hua University , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Keh-Chyang
authors.initials: KC
authors.lastname: Leou
authors.affiliation: Department of Physics, Tamkang University , New Taipei City 251, Taiwan, R.O.C.
authors.forename: I-Nan
authors.initials: IN
authors.lastname: Lin
authors.affiliation: Department of Materials Science and Engineering, National Tsing-Hua University , Hsinchu 300, Taiwan, R.O.C.
authors.forename: Nyan-Hwa
authors.initials: NH
authors.lastname: Tai
keywords: N-UNCD; electron field emission properties; strengthen carbon nanotubes (s-CNTs)