Electro-optical analysis in determining the field emission characteristics of carbon nanofibers on an acute tip substrate

Norihiro Shimoi, Yasumitsu Tanaka

Research output: Contribution to journalArticlepeer-review


The shape of an acute tungsten (W) tip substrate coated with palladium (Pd) and carbon nanofibers (CNFs) was optimized in order to generate efficient field emission (FE) currents. By adjusting the apex angle of the tip, we succeeded in controlling the FE properties and electron beam convergence. When the apex angle was close to 50°, a narrow convergence of electron beams was observed. By employing an original computation tool based on the surface charge method, we conducted a numerical analysis of the convergence mechanism of the FE device; this was dependent on FE properties, and displayed its maximum around the same apex angle. By simulating the electrical field distribution above the CNF, we concluded that the optimum values of the electro-optical properties of CNFs on the tip substrate were found at an angle of approximately 50° with a narrow divergence angle. After determining the relationship between the divergence angle and the tip apex angle, the electron emission property was optimized. Analysis of the characteristics of the maximum electron emission state using our computation method indicated that an acute tip covered with CNFs has potential for use as a cathode in electrical devices which require a large FE current with low power consumption.

Original languageEnglish
Pages (from-to)23-28
Number of pages6
JournalDiamond and Related Materials
Publication statusPublished - 2012 Sept


  • Carbon nanofiber
  • Divergence angle
  • Electro-optics
  • Electron field emission
  • Surface charge method
  • Tip substrate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Mechanical Engineering
  • Materials Chemistry
  • Electrical and Electronic Engineering


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