title: CO2 enhanced chemical vapor deposition growth of few-layer graphene over NiO(x).
abstract: The use of mild oxidants in chemical vapor deposition (CVD) reactions has proven enormously useful. This was also true for the CVD growth of carbon nanotubes. As yet though, the use of mild oxidants in the CVD of graphene has remained unexplored. Here we explore the use of CO2 as a mild oxidant during the growth of graphene over Ni with CH4 as the feedstock. Both our experimental and theoretical findings provide in-depth insight into the growth mechanisms and point to the mild oxidants playing multiple roles. Mild oxidants lead to the formation of a suboxide in the Ni, which suppresses the bulk diffusion of C species suggesting a surface growth mechanism. Moreover, the formation of a suboxide leads to enhanced catalytic activity at the substrate surface, which allows reduced synthesis temperatures, even as low as 700 °C. Even at these low temperatures, the quality of the graphene is exceedingly high as indicated by a negligible D mode in the Raman spectra. These findings suggest the use of mild oxidants in the CVD fabrication as a whole could have a positive impact.
authors.affiliation: Samsung Advanced Institute of Technology, Samsung Electronics Company, LTD , 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.
authors.forename: In Hyuk
authors.initials: IH
authors.lastname: Son
authors.forename: Hyun Jae
authors.initials: HJ
authors.lastname: Song
authors.forename: Soonchul
authors.initials: S
authors.lastname: Kwon
authors.forename: Alicja
authors.initials: A
authors.lastname: Bachmatiuk
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Anass
authors.initials: A
authors.lastname: Benayad
authors.forename: Jong Hwan
authors.initials: JH
authors.lastname: Park
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Hyuk
authors.initials: H
authors.lastname: Chang
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rümmeli
keywords: CO2; CVD; Ni; chemical vapor deposition; graphene