Selective Mechanical Transfer of Graphene from Seed Copper Foil Using Rate Effects

A very fast, dry transfer process based on Mechanical delamination successfully effected the transfer of large-area, (VD 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 mu m/s), monolayer graphene was completely transferred from the copper foil to the target silicon substrate. On the other hand, the lowest rate (25.4 mu m/s) caused the epoxy to be completely separated from the graphene. Fracture mechanics analyses were used to determine the adhesion energy between grapheiie and its seed copper foil (6.0 J/m(2)) and between graphene and the epoxy (3.4 J/m(2)) 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.