title: Direct transfer of multilayer graphene grown on a rough metal surface using PDMS adhesion engineering.
abstract: The direct transfer of graphene using polydimethylsiloxane (PDMS) stamping has advantages such as a 'pick-and-place' capability and no chemical residue problems. However, it is not easy to apply direct PDMS stamping to graphene grown via chemical vapor deposition on rough, grainy metal surfaces due to poor contact between the PDMS and graphene. In this study, graphene consisting of a mixture of monolayers and multiple layers grown on a rough Ni surface was directly transferred without the use of an adhesive layer. Liquid PDMS was cured on graphene to effect a conformal contact with the graphene. A fast release of graphene from substrate was achieved by carrying out wet-etching-assisted mechanical peeling. We also carried out a thermal post-curing of PDMS to control the level of adhesion between PDMS and graphene and hence facilitate a damage-free release of the graphene. Characterization of the transferred graphene by micro-Raman spectroscopy, SEM/EDS and optical microscopy showed neither cracks nor contamination from the transfer. This technique allows a fast and simple transfer of graphene, even for multilayer graphene grown on a rough surface.
authors.affiliation: Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea. KAIST Institute for the Nanocentury, Daejeon 34141, Korea.
authors.forename: Heejun
authors.initials: H
authors.lastname: Jang
authors.forename: Il-Suk
authors.initials: IS
authors.lastname: Kang
authors.forename: Youngbok
authors.initials: Y
authors.lastname: Lee
authors.forename: Yun Jeong
authors.initials: YJ
authors.lastname: Cha
authors.forename: Dong Ki
authors.initials: DK
authors.lastname: Yoon
authors.forename: Chi Won
authors.initials: CW
authors.lastname: Ahn
authors.forename: Wonhee
authors.initials: W
authors.lastname: Lee