Process to remove chemical vapor deposited (CVD) graphene from the backside of copper foil by floating on a dilute nitric acid solution. A polymethyl-methacrylate (PMMA) thin film protects the front side of graphene/copper foil.
Step
Description
1
Spin coating of e-beam resist (PMMA A6) on one side of the graphene/copper foil/graphene at 3000 rpm for 1 minute
2
Curing of PMMA/graphene/copper/graphene either at 37°C for 3 hours on a hot plate or at room temperature (21°C) in a vented hood for 12 hours
3
Etching of graphene on the backside of PMMA/graphene/copper/graphene by floating on a solution of HNO3/H2O (1 : 10) for ∼10–15 minutes
4
Rinsing of PMMA/graphene/copper by floating on distilled water for 3 minutes. Repeat three times the procedure
5
Drying of PMMA/graphene/copper foil with a nitrogen gun
