Direct graphene growth on (111) Cu2O templates with atomic Cu surface layer

• Published in: Carbon (New York) 2015-12, Vol.95, p.608-615
• Main Authors: Liu, Jianwei, Liu, Qingfeng, Baca, Javier, Xu, Guowei, Rochford, Caitlin, Lu, Rongtao, Edwards, Christina M., Berrie, Cindy L., Maroni, Victor A., Wu, Judy
• Format: Article
• Language: English
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2015.08.071

This work explores nucleation and epitaxy of graphene on crystalline Cu2O templates formed via self-assembly and surface reduction of Cu2O nanocrystallites on the cubic textured (100) orientation Cu (CTO-Cu) and polycrystalline Cu (poly-Cu) substrates, respectively. It has been found that the presence of sub-surface oxygen causes the reconstruction of Cu surface due to the formation of oriented Cu2O nanocrystallites at a low H2 gas flow. Self-assembly of the Cu2O nanocrystallites into a textured surface template provides direct nucleation sites for graphene growth after the oxygen-sublattice on the template surface is reduced. The atomic Cu surface layer provides advantages of high graphene growth rate due to the catalytic role of Cu and in-plane alignment of graphene nuclei. It is particularly important that the Cu2O crystallites have predominantly (111) orientation aligned to each other in the plane of the (100) CTO-Cu substrates, which allows epitaxy of graphene with much lower defect density as compared to that in the poly-Cu case. Since Cu2O (111) templates may be developed on lattice matched (100) surfaces of other dielectric materials, this self-assembly approach provides a promising pathway for large-scale, transfer free graphene epitaxy on nonmetallic surfaces.