Copper- Germanium-Graphene Based Highly Sensitive Plasmonic Biosensor For Protein Detection

In this paper, a surface plasmon resonance biosensor with improved sensitivity is proposed. We have used copper (Cu) as plasmonic material for ensuring long-term stability of plasmonic performance. Moreover, for the prevention of oxidation of copper, the germanium layer is employed. The inclusion of a thin layer of graphene on the top ensures used as biomolecular recognition element. For the modelling and determining the performance of the protein sensor, finite difference time domain (FDTD) method is used. From the result of numerical calculation, it is found that by using a germanium layer the sensitivity of graphene based SPR biosensor is increased 116 deg/RIU while it is 100 deg/RIU by using only a graphene layer which is 16% more sensitive. In addition, by increasing the number of graphene layer the sensitivity increased nonlinearly. Our proposed SPR sensor showing promising results can be an appropriate candidate for the protein detection.