Study of effect of nanomaterial above the add layer on performance parameters of plasmonic structure

In this paper, we explored the effect of adding a nanomaterial layer above the add layer on performance parameter of the considered plasmonic structures (conventional, four and five layer SPR sensors). These structures are stimulated by the COMSOL Multiphysics. We have considered LiNbO₃ as an add layer over a thin film of gold. Further, Graphene, Black Phosphorene, Mxene, MoS₂ MoSe_2, WS₂ and WSe₂ as nanomaterial are considered over add-layer. First, we optimised the thickness gold and LiNbO₃. After that, we calculated reflectance and magnetic field dependent performance parameters, i.e., shift in resonance angle (∆θ_r), full beam width (FBW), sensitivity (S), detection accuracy (DA), quality factor (Q. F.), figure of merit (FoM), field intensity at different interfaces (metal-sensing medium (M-S), metal-dielectric (M-D), dielectric-sensing medium (D-S), dielectric-nanomaterial (D-N), nanomaterial-sensing medium (N-S), and penetration depth (PD) for the considered plasmonic structures. The minimum ∆θr is obtained for conventional structure i.e. 1.492° and maximum ∆θr is obtained for WS₂ as nanomaterial used in five layer SPR sensor i.e., 2.052°. Moreover, FBW is also maximum for five layer SPR sensor with WS₂ as nanomaterial i.e., 6.8430°. Moreover, PD has maximum value for conventional SPR sensor i.e., 190.894 nm, 175.94 nm for four layer SPR sensor and less than 175.94 nm for five layer SPR sensor. This comparative study will help to choose add-layer with nanomaterial over add layer and metal thin film layer in a SPR sensor for the detection of analyte or molecules present in the sensing medium.