Sensitivity Enhancement of the Surface Plasmon Resonance Biosensor Based on Hybrid Structure Using MXene and MoS₂ for Refractive Index Sensing: An Angular Interrogation Approach

This paper proposes a surface plasmon resonance (SPR) biosensor based on the Kretschmann configuration including a bilayer of silver metal (Ag), molybdenum disulfide (MoS₂), molybdenum trioxide (MoO₃), titanium carbide MXene (Ti₃C₂T_x), and a BK7 coupling prism. The proposed device is designed as a refractive index sensor for hemoglobin measurement in human blood samples. The finite difference time domain (FDTD) technique has been used to evaluate the performance parameters of the sensor. Silver metal and 2D material thickness is optimized using an angular interrogation technique to minimize reflectance. The proposed biosensor exhibits the maximum sensitivity (S) of 218 deg/RIU, at a sensing medium of 1.32919–1.34919 with Δn_s = 0.005 RIU. Other parameters a detection accuracy of 0.182 deg⁻¹, a figure of merit of 40.63 RIU⁻¹, and a limit of detection of 4.587 × 10^–6 have been obtained. The proposed SPR biosensor effectively increases the strength of the interaction between the incident light and the analyte, resulting in a relatively reduced propagation loss. Therefore, the suggested sensor is a suitable candidate to detect and analyze biomolecules.