title: In Situ Graphene Growth Dynamics on Polycrystalline Catalyst Foils.
abstract: The dynamics of graphene growth on polycrystalline Pt foils during chemical vapor deposition (CVD) are investigated using in situ scanning electron microscopy and complementary structural characterization of the catalyst with electron backscatter diffraction. A general growth model is outlined that considers precursor dissociation, mass transport, and attachment to the edge of a growing domain. We thereby analyze graphene growth dynamics at different length scales and reveal that the rate-limiting step varies throughout the process and across different regions of the catalyst surface, including different facets of an individual graphene domain. The facets that define the domain shapes lie normal to slow growth directions, which are determined by the interfacial mobility when attachment to domain edges is rate-limiting, as well as anisotropy in surface diffusion as diffusion becomes rate-limiting. Our observations and analysis thus reveal that the structure of CVD graphene films is intimately linked to that of the underlying polycrystalline catalyst, with both interfacial mobility and diffusional anisotropy depending on the presence of step edges and grain boundaries. The growth model developed serves as a general framework for understanding and optimizing the growth of 2D materials on polycrystalline catalysts.
authors: Department of Engineering, University of Cambridge , Cambridge CB3 0FA, United Kingdom.|Materials Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley California 94720, United States.
authors: Robert S
authors: RS
authors: Weatherup
authors: Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States.
authors: Ashwin J
authors: AJ
authors: Shahani
authors: Fritz Haber Institute , Faradayweg 4-6, D-14195 Berlin, Germany.
authors: Zhu-Jun
authors: ZJ
authors: Wang
authors: National Physical Laboratory , Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom.
authors: Ken
authors: K
authors: Mingard
authors: National Physical Laboratory , Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom.
authors: Andrew J
authors: AJ
authors: Pollard
authors: Fritz Haber Institute , Faradayweg 4-6, D-14195 Berlin, Germany.
authors: Marc-Georg
authors: MG
authors: Willinger
authors: Fritz Haber Institute , Faradayweg 4-6, D-14195 Berlin, Germany.
authors: Robert
authors: R
authors: Schloegl
authors: Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States.
authors: Peter W
authors: PW
authors: Voorhees
authors: Department of Engineering, University of Cambridge , Cambridge CB3 0FA, United Kingdom.
authors: Stephan
authors: S
authors: Hofmann
keywords: Graphene; chemical vapor deposition; domain shape; growth dynamics; modeling; platinum