Probing substrate-induced perturbations on the band structure of graphene on Ni(1 1 1) by soft X-ray emission spectroscopy

The influence of substrate-induced perturbations on the band structure of graphene has been investigated by soft X-ray emission spectroscopy (XES) for graphene on Ni(1 1 1). The band-dispersion features of graphene on Ni(1 1 1) are different from those of HOPG and ‘quasi-freestanding’ graphene (graphene/Cu) because of the strong interfacial interaction. By comparing the XES spectra excited with energy at the π∗ resonance of HOPG, graphene/Cu and graphene/Ni in detail, we find that the spectral shape change can be directly related to the different electronic states hybridization strength of graphene on metal substrates, supplying a feasible way for investigating the graphene–metal bonding strength.