Graphene oxide on magnetron sputtered silver thin films for SERS and metamaterial applications

In the last years the potential of combining the attractive materials characteristics of graphene related materials and silver nanostructures for SERS and metamaterials has emerged. Here, we report of graphene oxide thin films deposited by dip-coating on magnetron sputtered silver thin films. Our work represents a novelty in the field of the study of graphene oxide- silver composites, since magnetron sputtering deposition is an alternative way to silver thin films fabrication; previous works used instead silver nitrate aqueous solution mixed with the graphene oxide. Micro-Raman technique, morphological analysis and variable angle spectroscopic ellipsometry were performed. The final SERS signal intensity was investigated and we found Raman peaks dependent on the intensity of the laser and the thickness of silver and GO films. These results could open somestudies on plasmonics and on the reduction of graphene oxide mediated by silver thin films. Moreover, effective medium theory calculations show the possible use of these graphene oxide/silver thin films in multilayer hyperbolic metamaterials for optical applications.