Graphene processing using electron beam assisted metal deposition and masked chemical vapor deposition growth

The fabrication of graphene devices can be challenging due to exposure to harsh chemicals and mechanical wear such as ultrasonication used for cleaning in photolithography and metal deposition. Common graphene processing methods often damage fragile graphene sheets and can ruin the device during fabrication. The authors report a facile method to overcome many of these challenges, which is specifically compatible with graphene grown by chemical vapor deposition (CVD). Using e-beam assisted metal deposition to deposit fine platinum features, electrodes can be deposited directly on graphene while still on the copper foil used as the catalyst during the CVD growth. The graphene and electrodes are then transferred to an insulating substrate, without further processing. This method preserves the graphene/metal interface from exposure to harsh chemicals used in traditional lithography methods, and avoids many of the conventional processing steps, which can cause unwanted doping, and damage or destroy the graphene. The authors observe an increase in Raman D-mode in the graphene under the Pt deposit, which suggests that the deposition method facilitates chemisorption by slightly abrading the surface of graphene surface during deposition. Using e-beam assisted electrode deposition in conjunction with masked CVD graphene growth on copper, the authors show the feasibility of fabricating complete graphene devices without subjecting the graphene to lithography, plasma etching, metal lift-off steps, or even shadow mask processing. VC 2016 American Vacuum Society. [http://dx.doi.org/10.1116/1.4958795]