Discontinuity and misorientation of graphene grown on nickel foil: Effect of the substrate crystallographic orientation Jekaterina Kozlova a , Ahti Niilisk a , Harry Alles a , Va¨ ino Sammelselg a,b, * a University of Tartu, Institute of Physics, Ravila 14c, 50411 Tartu, Estonia b University of Tartu, Institute of Chemistry, Ravila 14a, 50411 Tartu, Estonia ARTICLE INFO Article history: Received 2 March 2015 Accepted 13 June 2015 Available online 19 June 2015 ABSTRACT Graphene growth by chemical vapor deposition on low cost metal foils is a promising approach for the production of large-scale graphene. However, the precise control of the uniformity of synthesized mono- and multilayer graphene requires elucidation of the factors affecting deposition and growth. In this study, we investigate the influence of the crystallographic orientation of nickel on multilayer graphene growth using electron- backscatter diffraction, Raman and energy dispersive X-ray spectroscopies, as well as scanning electron and atomic force microscopies. We correlated the discontinuities of the graphene sheets on polycrystalline nickel foils with crystallographic orientations of nickel grains. In addition, we observed indications of misoriented (twisted) multilayer graphene on particular grain orientations. We demonstrate that the Raman signature from these misoriented multilayer graphene areas is highly similar to that previously reported for twisted bilayer graphene. Using microscopy methods, we demonstrated dramatic morphological changes in the nickel substrate induced by graphene growth. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction Since the isolation of graphene in 2004 [1], the number of pro- posed applications of graphene is continuing to grow. To take graphene out of the lab for applications on the industrial level, a reproducible method for large-scale synthesis of high-quality homogenous graphene is required. Chemical vapor deposition (CVD) on transition metal surfaces is a potentially useful approach. From an industrial point of view, copper and nickel catalysts are of particular interest due to their availability and low cost. In addition, these catalysts can be readily etched to allow the synthesized graphene to be transferred to the desired substrate. A self-limiting growth mechanism on copper allows for the production of a predom- inantly single layer graphene (SLG). Because carbon solubility in copper is negligible, the growth stops when the entire sur- face is covered with graphene. The synthesis of monolayer graphene on nickel is more challenging due to precipitation-induced growth and is generally achieved on single crystalline substrates in ultra-high vacuum [2,3]. Few- layer graphene (FLG) and multilayer graphene (MLG) are obtained at standard CVD conditions, where the number of graphene layers can be controlled by varying the thickness of the underlying nickel substrate or the time of hydrocarbon http://dx.doi.org/10.1016/j.carbon.2015.06.023 0008-6223/Ó 2015 Elsevier Ltd. All rights reserved. * Corresponding author at: University of Tartu, Institute of Physics, Ravila 14c, 50411 Tartu, Estonia. E-mail address: vaino.sammelselg@ut.ee (V. Sammelselg). CARBON 94 (2015) 160 – 173 Available at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/carbon