Ingenious design of Cu/Ni substrate for hot filament chemical vapor deposition growth of high quality graphene films

The Cu/Ni substrates were fabricated at low defect densities of the Ni substrates by RF magnetron sputtering and the composition of Cu atoms on Ni substrates were modulated by the sputtering time. The high-quality graphene films were fabricated on the Cu/Ni substrates by hot filament chemical vapor deposition system (HFCVD). The I_D/I_G ratios were very low (<<0.1) for all samples, which reflected the high-quality graphene films were obtained. The composition of Cu atoms played an important role in the growth of graphene films. Based on the dissolution precipitation mechanism of Ni and the absorption and self-limiting mechanism of Cu on the Cu/Ni substrates, it has been found that the layers of graphene was restrained by the composition of Cu atoms. Different layers of high-quality graphene films were obtained. A new growth mechanism of fabrication method was proposed by this investigation.