Simultaneously enhanced electrical conductivity and strength in Cu/graphene/Cu sandwiched nanofilm

Cu/graphene/Cu sandwiched nanofilms with a thickness of ~100 nm were prepared on SiO2/Si substrates by a combined process of magnetron sputtering and graphene transfer. Except for an enhancement of 14.9% on hardness as compared to Cu/Cu nanofilms, the as-sputtered and annealed sandwiched nanofilms show improvements on electrical conductivity by 18.0% and 17.2%, respectively. By using Raman spectroscopy, the enhancement mechanism on electrical conductivity was investigated with respect to electron doping, and strain effect on the band gap of graphene and thus the doping concentration was also discussed.