Oil boundary approach for sublimation enabled camphor mediated graphene transfer

Transfer of chemical-vapor-deposition (CVD) grown monolayer graphene from one substrate to another requires a transfer agent. The transfer agent usually needs to be removed by washing with organic solvent such as acetone or high temperature annealing, which is harmful to the structure integrity and intrinsic property of a graphene film. Here, we propose the use of camphor as a transfer agent to transfer monolayer graphene onto a target dielectric substrate, which bypasses these demanding steps and only needs the common alcohol solvent rinsing.

To facilitate a crack-free graphene transfer, the proposed approach allows the camphor supported polycrystalline graphene to be rationally fastened with a thickened and solidified edge bead (i.e. camphor oil-filled boundary). A layer of camphor was first deposited onto a graphene/copper surface. The backside copper substrate was then etched away, whilst the camphor/graphene bilayer was placed onto a SiO₂/Si substrate. Finally, the camphor remaining on the camphor/graphene/SiO₂/Si sublimed into a vapor. The graphene/SiO₂ stack was then examined by microscopic, spectral and electrical characterization.

The results of our examination suggest that the proposed method can guarantee a clean and damage-free graphene transfer. This method is particularly attractive in the application area for nano/micro-electronics, where it provides CVD-grown graphene the ability to be used on wide varieties of substrates that are sensitive to organic solvents and high temperature.