Effect of Gas Atmosphere in the Heating Stage on Limiting Nucleation of Graphene on Copper Foils by Low Pressure Chemical Vapor Deposition

To investigate the effect of gas atmosphere in the heating stage of graphene fabrication on graphene nucleation, hydrogen and nitrogen are introduced into the furnace respectively in the heating stage. The results show that graphene growing on copper foils heated in nitrogen atmosphere and in hydrogen atmosphere present different nucleation characteristics. The analysis implies that the gas atmosphere in the heating stage affects the graphene nucleation and growth by changing the morphology of the copper surface and the inherent carbon concentration in the substrate, and this change actually results from the interaction of the copper surface and the gas atmosphere. The difference in size and quality of the fabricated graphene domains also indicates nitrogen atmosphere in the heating stage favors fabricating large-sized graphene domains with good quality. Thus, substituting hydrogen for nitrogen in the heating stage would be a simpler and easier way to depress graphene nucleation as well as improve the graphene quality.