Deposition of various materials onto graphene without causing any disorder is highly desirable for graphene applications. Especially, sputtering is a versatile technique to deposit various metals and insulators for spintronics, and indium tin oxide t
o make transparent devices. However, the sputtering process causes damage to graphene because of high energy sputtered atoms. By flipping the substrate and using a high Ar pressure, we demonstrate that the level of damage to graphene can be reduced or eliminated in dc, rf, and reactive sputtering processes.
Tunability of the surface plasmon resonance wavelength is demonstrated by varying the thickness of Al2O3 spacer layer inserted between the graphene and nanoparticles. By varying the spacer layer thickness from 0.3 to 1.8 nm, the resonance wavelength
is shifted from 583 to 566 nm. The shift is due to a change in the electromagnetic field coupling strength between the localized surface plasmons excited in the gold nanoparticles and a single layer graphene film. In contrast, when the graphene film is absent from the system, no noticeable shift in the resonance wavelength is observed upon varying the spacer thickness.
