title: Microstructural Evolution of Nanocrystalline Diamond Films Due to CH4/Ar/H2 Plasma Post-Treatment Process.
abstract: Plasma post-treatment process was observed to markedly enhance the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films. TEM examinations reveal that the prime factor which improves the EFE properties of these films is the coalescence of ultrasmall diamond grains (∼5 nm) forming large diamond grains about hundreds of nanometers accompanied by the formation of nanographitic clusters along the grain boundaries due to the plasma post-treatment process. OES studies reveal the presence of large proportion of atomic hydrogen and C2 (or CH) species, which are the main ingredients that altered the granular structure of the UNCD films. In the post-treatment process, the plasma interacts with the diamond films by a diffusion process. The recrystallization of diamond grains started at the surface region of the material, and the interaction zone increased with the post-treatment period. The entire diamond film can be converted into a nanocrystalline granular structure when post-treated for a sufficient length of time.
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University , Hsinchu, Taiwan 300, R.O.C.
authors.forename: Sheng-Chang
authors.initials: SC
authors.lastname: Lin
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University , Hsinchu, Taiwan 300, R.O.C.
authors.forename: Chien-Jui
authors.initials: CJ
authors.lastname: Yeh
authors.affiliation: Department of Physics, Tamkang University , Tamsui, Taiwan 251, 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, Taiwan 300, R.O.C.
authors.forename: Keh-Chyang
authors.initials: KC
authors.lastname: Leou
authors.affiliation: Department of Physics, Tamkang University , Tamsui, Taiwan 251, R.O.C.
authors.forename: I-Nan
authors.initials: IN
authors.lastname: Lin
keywords: diamond films; electron field emission; microstructure; nanocrystalline; post-treatment