Graphene-based Surface Plasmon Resonance Urea Biosensor using Kretschmann configuration

The present paper analyses a surface plasmon resonance (SPR) biosensor based on graphene that leads to improvement on efficiency of an urea biosensor due to high adsorption. Kretschmann configuration is well known as the most effectively used technique for plasmon excitation. In this work, we investigated the effect of MoS2 with a fine layer of graphene deposited on a plasmonic material, gold (Au), into the configuration. Simulation is based on finite-difference time-domain (FDTD) method for analysis. The performance of SPR biosensor can be monitored by analyzing the sensitivity and full-width-at-half-maximum (FWHM) of the SPR spectrum. The measurements are observed at 670 nm and 785 nm for urea detection. The molarity and refractive index is varied from 1.335 to 1.347 for sensing layer. The results show that maximum sensitivity of as high as 230 degrees/RIU and 173.16 degrees/RIU can be achieved at 670 nm and 785 nm respectively, which indicates the proposed SPR biosensor is suitable for urea detection.