Sensitivity enhancement of a graphene-barium titanate-based surface plasmon resonance biosensor with an Ag-Au bimetallic structure in the visible region

In this study, a surface plasmon resonance (SPR) biosensor based on graphene-barium titanate nanocomposites is optimized by using an Ag-Au bimetallic configuration to achieve sensitivity enhancement. The angular interrogation method is used for the analysis of the reflectance from the sensor. By optimizing parameters, a sensitivity and figure of merit as high as 294 degrees/RIU and 42.13 1/RIU can be obtained with Ag-Au bimetallic film at a wavelength of 633 nm. Compared with conventional SPR biosensors with a single metal film, the sensitivity of the proposed biosensor with Ag-Au bimetallic film can be greatly enhanced. Also, Au thin film can be used as a protective layer to prevent oxidation of the Ag layer. (C) 2019 Optical Society of America