Selective Mechanical Transfer of Graphene from Seed Copper Foil Using Rate Effects
journal contributionposted on 24.02.2015 by Seung Ryul Na, Ji Won Suk, Li Tao, Deji Akinwande, Rodney S. Ruoff, Rui Huang, Kenneth M. Liechti
Any type of content formally published in an academic journal, usually following a peer-review process.
A very fast, dry transfer process based on mechanical delamination successfully effected the transfer of large-area, CVD grown graphene on copper foil to silicon. This has been achieved by bonding silicon backing layers to both sides of the graphene-coated copper foil with epoxy and applying a suitably high separation rate to the backing layers. At the highest separation rate considered (254.0 μm/s), monolayer graphene was completely transferred from the copper foil to the target silicon substrate. On the other hand, the lowest rate (25.4 μm/s) caused the epoxy to be completely separated from the graphene. Fracture mechanics analyses were used to determine the adhesion energy between graphene and its seed copper foil (6.0 J/m2) and between graphene and the epoxy (3.4 J/m2) at the respective loading rates. Control experiments for the epoxy/silicon interface established a rate dependent adhesion, which supports the hypothesis that the adhesion of the graphene/epoxy interface was higher than that of the graphene/copper interface at the higher separation rate, thereby providing a controllable mechanism for selective transfer of graphene in future nanofabrication systems such as roll-to-roll transfer.