PEEM and micro PES study of graphene growth on Ni(110) substrate

Graphene growth on a carbon-doped Ni(110) substrate by surface segregation and surface precipitation has been investigated by photoelectron emission microscopy (PEEM) and micro photoelectron spectroscopy (μ-PES). Single-layer and multi-layer graphenes were found to grow on the substrate with anisotropic shape, which indicate the strong effect on the growth from the Ni(110) substrate. Most of the surface was covered by thick multi-layer graphene when the precipitation had been made with the cooling rate 0.8°C/s, while small domains of single-layer graphene and a few-layer graphene grew on the bare Ni(110) substrate by the rapid cooling (4.1°C/s). The layer dependent work functions have been measured by μ-PES. The work functions were 4.2, 4.4 and 4.6 eV for the single, double and > 3 layers graphene on the Ni(110) substrate, respectively. The μ-PES measurement with He-I reveals the shift of the final state peak characteristic to graphite or graphene depending on the number of layers.