Performance Enhancement of a Novel Surface Plasmon Resonance Biosensor Using Thallium Bromide.

In this paper, we present the performance enhancement of the SPR biosensor using a novel dielectric material of thallium bromide (TIBr). The proposed structure comprised of six layers, including BK7 prism, silver (Ag), aluminum arsenide (AlAs), TIBr, black phosphorus (BP), and a sensing layer. In this investigation, we have considered four structures using the above-defined layers for the performance comparison and heightened the impact of TIBr in the proposed SPR sensor. The performance analysis is studied numerically at 633nm wavelength by considering the angular interrogation method and it endorsed with the wavelength variation method as well as the electric field intensity performance, employing the transfer matrix method and the FDTD solutions. The proposed structure is referred to as structure-IV is achieved the sensitivity of 475°/RIU compared to structures- III, II, I that have the sensitivities of 155, 120, 105°/RIU, respectively, at the minimal unit changes in the refractive index of the biomolecules. In addition, the proposed structure facilitates a quality factor of 80.37 and a figure of merit of 79.72. This investigation is introduced the performance of combined sensitive factor (CSF) of 77.9, which shows the SPR's overall performance. In order to observe the wavelength resolution, the sensor's sensitivity is investigated for different wavelengths at different metal thicknesses. Finally, the proposed structure's performance is compared with the existing works, demonstrating that the proposed SPR sensor can be established as a new platform for researchers in the field of bio-sensing applications.