Influence of Copper Morphology in Forming Nucleation Seeds for Graphene Growth

• Published in: Nano letters Vol. 11; no. 10; pp. 4144 - 4148
• Main Authors: Han, Gang Hee, Güneş, Fethullah, Bae, Jung Jun, Kim, Eun Sung, Chae, Seung Jin, Shin, Hyeon-Jin, Choi, Jae-Young, Pribat, Didier, Lee, Young Hee
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.10.2011
• Subjects: Condensed matter: structure, mechanical and thermal properties; Copper; Cross-disciplinary physics: materials science; rheology; Crystal structure; Density; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General studies of phase transitions; Graphene; Materials science; Monolayers; Morphology; Nucleation; Physics; Polished; Seeds; Specific materials; Graphene, Chemical vapor deposition, Seed, Copper, Wrinkle; Grain boundaries; Scratching test; Crystal defects; Nucleation; Multilayer; Surface morphology; Crystal seeds; Thin films; Multilayers; Sheet resistivity; Graphene; Monolayers; Growth mechanism; Copper; Chemical mechanical polishing
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl201980p

We report that highly crystalline graphene can be obtained from well-controlled surface morphology of the copper substrate. Flat copper surface was prepared by using a chemical mechanical polishing method. At early growth stage, the density of graphene nucleation seeds from polished Cu film was much lower and the domain sizes of graphene flakes were larger than those from unpolished Cu film. At later growth stage, these domains were stitched together to form monolayer graphene, where the orientation of each domain crystal was unexpectedly not much different from each other. We also found that grain boundaries and intentionally formed scratched area play an important role for nucleation seeds. Although the best monolayer graphene was grown from polished Cu with a low sheet resistance of 260 Ω/sq, a small portion of multilayers were also formed near the impurity particles or locally protruded parts.