Graphene Growth by a Metal-Catalyzed Solid-State Transformation of Amorphous Carbon

Single and few-layer graphene is grown by a solid-state transformation of amorphous carbon on a catalytically active metal. The process is carried out and monitored in situ in an electron microscope. It is observed that an amorphous carbon film is taken up by Fe, Co, or Ni crystals at temperatures above 600 °C. The nucleation and growth of graphene layers on the metal surfaces happen after the amorphous carbon film has been dissolved. It is shown that the transformation of the energetically less favorable amorphous carbon to the more favorable phase of graphene occurs by diffusion of carbon atoms through the catalytically active metal.