The broad strokes of the process is:
a) PMMA [Poly(methyl methacrylate)] in an anisole solvent is spin coated onto the surface of the copper and cured in a vacuum.
b) The graphene coating the underside of the foil is then removed using an argon/oxygen plasma in a reactive ion etcher.
c) The foil is floated on the surface of an etchant solution where the etchant is nitric acid diluted 1:7 with ultrapure deionised water. 1Mol FeCl3 solution is also used as an alternative etchant of the transfer process for graphene grown on nickel and copper.
d) Once the copper is fully etched, the PMMA support and graphene are transferred in to ultrapure deionised water. The film is repeatedly transferred to water to clean the graphene surface from the residuals of the etchant solution.
e) The film is lifted out of the ultrapure deionised water by a substrate and left to dry.
f) Finally, the PMMA support layer is removed using acetone, followed by an isopropyl alcohol (IPA) rinse and drying with nitrogen.
a) Copper foil is spin coated with PMMA, b) the graphene on the underside of the copper is etched using an argon plasma, c) the copper is etched in a dilute solution of nitric acid in ultrapure deionised water, d) the film is spoon transferred in ultrapure deionised water, e) the film is lifted from solution using a substrate, f) the film is left to dry prior to removal of the PMMA support.
This whole process can be performed using out manual and automatic graphene transfer machines. The kits provide everything needed to perform graphene transfers from any size up to 4”.
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