Transfer of Graphene with Protective Oxide Layers

Transfer of graphene, grown by Chemical Vapor Deposition (CVD) on copper, to a substrate of choice, involves deposition of a polymeric layer (typically, poly(methyl methacrylate or polydimethylsiloxane, PDMS). These polymers are quite hard to remove without leaving some residues behind. Since many applications require deposition of an oxide top gate film, we set to explore the transfer of graphene with a protective thin oxide layer. The oxide layer was grown by Atomic Deposition Layer (ALD) on the graphene right after the growth stage on Cu foils. One can further aid the oxide-graphene transfer by depositing a thin polymer layer on top of the composite (much thinner than the usual film thickness used) following by a more aggressive polymeric removal methods while keeping the graphene intact. The overall result is a polymer-free graphene topped with a thin oxide layer.