Performance Enhancement of SPR sensor in NIR-Region for urea detection using MoS2-Dielectric materials-MnS2 Based Structure

Most researchers proposed the surface plasmon resonance (SPR) sensor in the visible light range only. This paper presents performance enhancement of SPR sensor based on molybdenum disulphide (MoS
2
)-Dielectric matertals-MoS
2
-structure in Near Infrared (NIR) region for urea detection. The proposed structure consists of six layers, and the gold (Au) is used as a plasmonic material to improve its performance. The double MoS
2
layers are coated on both surfaces of dielectric materials such as germanium oxide (GeO
2
) and gallium phosphide (GaP), which are used as protective layers and bio-recognition elements to enhance SPR performance. In this study, we have considered two different urea concentrations of 2.5 and 5gm/dl as a sensing medium, having RIs of 1.339 and 1.342, whereas the normal urea RI is 1.335. The performance is analyzed numerically at 785nm wavelength applying the transfer matrix method. Initially, the performance investigates the optimized thickness of Au using the iteration method. Further, the outcome results are shown in terms of sensitivity and quality factor (QF), and the maximum achieved performances are S of 280°/RIU and QF of 41.36RIU
⁻¹
at a change in sensing RI of 0.007. Finally, the proposed structure performance is compared to existed SPR structures done by other researchers.