title: Effect of gas phase composition cycling on/off modulation numbers of C2H2/SF6 flows on the formation of geometrically controlled carbon coils.
abstract: Carbon coils can be synthesized using C2H2/H2 as source gases and SF6 as an incorporated additive gas under a thermal chemical vapor deposition system. In this study, nickel catalyst layer deposition and then hydrogen plasma pretreatment were performed prior to the carbon coils deposition reaction. To obtain geometrically controlled carbon coils, source gases and SF6 were manipulated as the cycling on/off modulation numbers of C2H2/SF6 flows. The cycling numbers were varied according to the different reaction processes. The increased cycling numbers could develop the wave-like nano-sized carbon coils. By further increasing the cycling numbers, however, the nanostructured carbon coils seemed to deteriorate. As a result, the maximum formation of geometrically controlled carbon coils was achieved by adjusting the cycling numbers. The enhanced etching capability of the fluorine-related species in SF6 additive gas was considered for the main objective of controlling the geometry of carbon coils.
authors.affiliation: Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736, Republic of Korea.
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Eum
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Jeon
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim