The field emission characteristics of hydrogenated amorphous carbon (a-C:H) films prepared by helical resonator-plasma enhanced chemical vapor deposition (HR-PECVD) are examined. a-C:H films are deposited with CH4/H2 and CH4/Ar gases under different substrate RF bias conditions. The properties of a-C:H films are investigated by Raman spectroscopy, Fourier transform IR (FT-IR), UV spectroscopy and elastic recoil detection (ERD). Field emission characteristics of a-C:H coated on Si whiskers which are grown by the vapor-liquid-solid (VLS) method are tested under ultrahigh vacuum. Highly efficient field emission characteristics are achieved in the specimen deposited at a substrate RF bias higher rather than in the ground deposition condition regardless of the nature of the reactant gas. As the substrate RF bias is changed from ground to a higher RF substrate bias, the deposited a-C:H films have lower hydrogen contents and higher sp2-bonds. Therefore, the field emission characteristics of a-C:H thin films are affected by the hydrogen contents of the films rather than by the sp3/sp2 ratio.
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Issue number||8 PART A|
|Publication status||Published - 1997 Aug 1|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)