Direct Synthesis of Graphene on SiO2 Substrates by Transfer-Free Processes

We have demonstrated the direct the synthesis of graphene on SiO2 substrates by transfer-free processes. An amorphous layer was sandwiched between a Ni layer and a SiO2/Si substrate, and then the sample was annealed under H-2 and Ar ambient. The measurements by scanning electron microscopy and Raman spectroscopy reveal that Ni islands were formed and that the 2D band was clearly observed at the region between Ni islands. From the intensity ratio of the G band to the 2D band, multilayer graphene was concluded to have been synthesized owing to the retraction of the Ni layer during annealing of the sample. (C) 2012 The Japan Society of Applied Physics