Thickness control of chemical vapor deposition-grown graphene film by oxygen plasma etching with recycled use of Ni catalyst

Ni has been widely used as one of the most important metal catalysts for graphene growth with the chemical vapor deposition (CVD) method. Despite the many advantages, it is difficult to obtain high quality graphene from Ni due to the complexity in controlling the uniformity and thickness of multilayer graphene films. In this study, the thickness of multilayer graphene films grown on Ni was controlled by single-step oxygen plasma etching. The results show that the thickness of the graphene films proportionally decreased with an increase in the plasma etching time where the thickness was controlled from thick graphite films to thin graphene films with a transparency over 80%. Surface topology after oxygen plasma etching showed that uniform etching was achieved, for which the topmost surface of the resulting thin graphene is hydrophilic because of oxygen plasma irradiation, which is advantageous for coating organic layers in device fabrication. Moreover, because of the absence of a metal etching process, the recycled use of Ni catalysts is available, increasing the cost efficiency.