Fig. 2
C 1s core-level SR-XPS spectrum. a Surface-sensitive SR-XPS spectrum obtained at the detection angle of 60° with respect to the surface normal. Inset is the relative peak intensity of graphene and Ni carbides (Ni3C and NiCx) normalized by that of SiC. b SR-XPS peak intensity ratio of graphene normalized by the Ni carbides (Ni3C and NiCx). c A model for the order of the stacking layers