Abstract:

Chemical vapor deposition (CVD) is an effective method for preparing large-size and high-quality graphene materials. The properties of the metal catalysts are direcly related to the quality of the prepared graphene films, so the surface pretreatment of the metal catalysts is required. In this study, the effects of different pretreatment methods on copper substrates are investigated, and the combination of passivation paste pickling and electrochemical polishing is proposed to be an effective method to modify the surface morphology of copper catalyst. The electrochemical polishing parameters (such as voltage, time) and the copper substrate annealing parameters (such as annealing temperature, time) are systematically studied. This study demonstrates that high electrochemical polishing voltage and long polishing time easily lead to the excessive polishing. It is appropriate to set the polishing voltage and polishing time to 8 V and 8 min, respectively. It is found that the annealing temperature and time have significant effects on the grain size of the copper catalyst. After annealing at 1000 ℃ for 30 min, the grain is larger and more uniform. In addition, the structure characterization of graphene prepared by CVD is also performed. According to the SEM image and Raman spectrum, the few-layer, high-quality graphene film is successfully prepared.

Key words: copper substrate, pretreatment, chemical vapor deposition, graphene