Influence of the transfer and chemical treatment of monolayer graphene grown for flexible transparent electrodes

• Published in: Carbon (New York) Vol. 81; pp. 458 - 464
• Main Authors: Kim, Yena, Kim, Hyeongkeun, Kim, Tae Young, Rhyu, Se Hyun, Choi, Dong Soo, Park, Won Kyu, Yang, Cheol-Min, Yoon, Dae Ho, Yang, Woo Seok
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2015; Elsevier
• Subjects: Acetone; Chloroform; Cross-disciplinary physics: materials science; rheology; Drying; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Graphene; Impurities; Materials science; Physics; Polymethyl methacrylates; Residues; Solvents; Specific materials; Ultrathin films; Electrodes; Graphene; Chemical treatment; Monolayers
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2014.09.078

It has become critically important to develop reliable method to transfer chemical vapor deposited (CVD) graphene from its growth substrate to the target substrate without leaving undesired polymer residues on the graphene surface. Here, we have found that for the two different transfer method – wet transfer using poly(methyl methacrylate) (PMMA) and dry transfer using polydimethylsiloxane (PDMS) as support layer, the amount of polymer residues and other impurities left on the graphene surface varies depending on the solvent used to remove those polymers. The exposure of the graphenes to different organic solvents such as acetone and chloroform resulted in different amount of polymer residues and impurities present on the graphene surface, which impact the electronic structure of the transferred graphene. It was found that the graphene obtained using the dry transfer method and acetone as solvent with a 2D to G (I2D/IG) intensity ratio of 4.58 and a 2D peak full width-half maximum (FWHM) of 24.66, which was higher than that using the wet transfer method and chloroform as solvent. These results showed that graphene was less affected by the polymer residues and impurities or the dry transfer method rather than the wet transfer method. In addition, using acetone rather than chloroform as solvent in the dry transfer method led to less contaminated graphene.