Effects of the Heating-up Atmosphere on the Nucleation of Graphene on Copper Foils

Abstract

Heated up in H₂ and N₂ respectively at the heating-up stage, the copper foils were used as the substrates to fabricate graphene by low pressure chemical vapor deposition. The fabricated graphene presented different characteristics. Heated up in H₂, on the substrate appeared polycrystalline films with small domains of poor quality; while in N₂, the size of the graphene domain was up to 500 μm with good quality. The results indicated that the heating-up atmosphere caused the differences in graphene morphology by changing the surface microstructure of the substrate. In N₂, the copper surface tended to become smoother, leading to difficult nucleation; while in H₂, plenty of terraced steps appeared on the surface of the substrate, providing much more favorable sites for active carbon atoms to cluster and nucleate.

Keywords:

• Atmosphere
• graphene
• nucleation
• growth
• terraced step
• mechanism

Additional information

Funding

This work was supported by the Natural Science Basic Research Plan in Shaanxi Province of China (No. 2017JQ5107), the Natural Science Foundation of Shaanxi Provincial Department of Education (No. 17JK0571), Panzhihua Municipal Science and Technology Project (No. 2017CYG18), and the National Natural Science Foundation of China (No. 51802260).