Graphene: A Building Foundation for Efficient Plasmonic SERS Device

In this paper graphene over SiO2/Si substrate was used as a building base to fabricate SERS device. A thin film of silver was deposited over graphene and annealed at 250°C. The substrate was examined after chemisorption of two molecules; rhodamine 6G which is a fluorescent dye, and 3-mercaptobenzoic acid, a thiol molecule. SERS enhancement factor for the proposed device is estimated to be 2.1 × 106 with respect to the flat silver substrate deposited over Si. The experimental results were compared in two ways: a) by using electromagnetic field calculation and b) quantum mechanical calculation derived from density function theory. The experimental findings were consistent with the theoretical observations.