Scanning tunneling microscopic investigations for studying conformational change of underlying Cu(111) and Ni(111) during graphene growth

Abstract

Demonstration of graphene growth on metal substrates using chemical vapor deposition method (CVD) facilitated the large-area synthesis of graphene, which extended the graphene research from the fundamental investigation with a small graphene flake to the various practical applications. Spectroscopic studies using C-13-labeled carbon precursor first suggested two different growth mechanisms of graphene on Ni and Cu substrates during the conventional CVD process, 'segregation growth' and 'sulfate growth' for Ni and Cu substrates, respectively. However, the growth mechanism of graphene is not simply understood. For example, the surface science studies have suggested the Ni2C conversion mechanism or the direct surface growth even on Ni surface. Herein, the conformational changes of underlying metal substrate during graphene growth on Ni(111) and Cu(111) are presented, which are highly affected by the different types of growth mechanisms. We believe that our results may widen the knowledge to understand the graphene growth mechanisms on Ni and Cu. Also, the influence of graphene-metal interaction on the electronic structures has been elucidated for graphene grown on Ni and Cu substrates by scanning tunneling spectroscopic studies combined with the theoretical calculation.