Graphene-based nano bio-sensor: Sensitivity improvement

In this paper, we attempt to present a multilayer-structure biosensor. A graphene-based Surface Plasmon Resonance (SPR) biosensor is considered as a structure, which offers enhancement of sensitivity in comparison with the conventional biosensors. The sensitivity improvement caused by the presence of graphene is discussed through monitoring of the biomolecular interactions and following that the Refractive Index (RI) changes. For this purpose, an RI change, which increases during the course of biomolecular interaction, is considered from 1.462 to 1.52. Our numerical results show that the proposed SPR biosensor with a graphene layer can provide a better sensitivity due to the field distribution at the binding region. This paper investigates the Sensitivity Enhancement Factor (SEF) according to the S-parameters and the effects of design parameters such as thicknesses of the gold and graphene layers and the refractive index change during the course of DNA hybridization in this biosensor.