Low-temperature synthesis of large-area graphene-based carbon films on Ni

Highlights: • Large-area multilayer graphene film was synthesized on poly-Ni surface at low temperatures (• A Ni-C-Ni sandwiched structure was used for growth of graphene both on poly-Ni free surface and along the Ni/SiO₂ interface; • TEM study revealed two synergistic growth mechanisms of graphene: stacking growth and crossing grain boundary growth; • The growth kinetics of graphene was scrutinized at different temperatures and for different times; • This work provides an attractive strategy for industrial scale manufacturing of large area graphene at low temperatures. In this work, large-area graphene-based carbon films were synthesized through a fast and low-temperature method. The processing route is illustrated on a free surface of Ni catalyst film by vacuum thermal processing of amorphous carbon. Key in the novel approach is that the synthesis is done at low temperatures, i.e. below 350 °C, and within a time as short as 1 min. The nucleation and growth of graphene on the free surface of nickel and along the interface between Ni film and SiO₂ substrate are investigated by using a thin film Ni-C-Ni sandwiched structure on a SiO₂/Si substrate. Raman spectroscopy demonstrates that the graphene-based carbon films consist of graphitic carbon rich of defects. HR-TEM observations reveal that the graphene-based carbon film grown on the top free surface is composed of thin multilayer graphene segments (3–6 atomic layers) and thick multilayer graphene segments (more than atomic 10 layers), covering the entire surface of Ni film over a large area. Growth parameters such as growth time, growth temperature and carbon/Ni ratio are reported in detail for a control of graphene growth kinetics. The results point at several attractive strategies for the facile synthesis of graphene-based carbon films for industrial applications.