title: Role of carbon nanotube interlayer in enhancing the electron field emission behavior of ultrananocrystalline diamond coated Si-tip arrays.
abstract: We improved the electron field emission properties of ultrananocrystalline diamond (UNCD) films grown on Si-tip arrays by using the carbon nanotubes (CNTs) as interlayer and post-treating the films in CH4/Ar/H2 plasma. The use of CNTs interlayer effectively suppresses the presence of amorphous carbon in the diamond-to-Si interface that enhances the transport of electrons from Si, across the interface, to diamond. The post-treatment process results in hybrid-granular-structured diamond (HiD) films via the induction of the coalescence of the ultrasmall grains in these films that enhanced the conductivity of the films. All these factors contribute toward the enhancement of the electron field emission (EFE) process for the HiDCNT/Si-tip emitters, with low turn-on field of E0 = 2.98 V/μm and a large current density of 1.68 mA/cm(2) at an applied field of 5.0 V/μm. The EFE lifetime stability under an operation current of 6.5 μA was improved substantially to τHiD/CNT/Si-tip = 365 min. Interestingly, these HiDCNT/Si-tip materials also show enhanced plasma illumination behavior, as well as improved robustness against plasma ion bombardment when they are used as the cathode for microplasma devices. The study concludes that the use of CNT interlayers not only increase the potential of these materials as good EFE emitters, but also prove themselves to be good microplasma devices with improved performance.
authors: †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Ting-Hsun
authors: TH
authors: Chang
authors: §Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Srinivasu
authors: S
authors: Kunuku
authors: ‡Department of Physics, Tamkang University, Tamsui 251, Taiwan, R.O.C.
authors: Joji
authors: J
authors: Kurian
authors: †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Afsal
authors: A
authors: Manekkathodi
authors: †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Lih-Juann
authors: LJ
authors: Chen
authors: §Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Keh-Chyang
authors: KC
authors: Leou
authors: †Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan, R.O.C.
authors: Nyan-Hwa
authors: NH
authors: Tai
authors: ‡Department of Physics, Tamkang University, Tamsui 251, Taiwan, R.O.C.
authors: I-Nan
authors: IN
authors: Lin
keywords: carbon nanotubes; electron field emission properties; hybrid granular structured diamond films; plasma illumination behavior; ultrananocrystalline diamond films