Design of an Advanced Sensor Based on Surface Plasmon Resonance with Ultra-High Sensitivity

This study presents the development of a high-sensitivity surface plasmon resonance (SPR) sensor featuring an innovative structure composed of a BK7 prism glass, copper (Cu) thin film, titanium dioxide (TiO₂), nickel (Ni), and a two-dimensional black phosphorus (BP) layer combined with a sensing medium. The sensor utilizes an angular interrogation technique, with its performance parameters sensitivity (S), detection accuracy (DA), and quality factor (QF) analyzed using the attenuated total reflection (ATR) and transfer matrix method (TMM). The results demonstrate significant improvements in the full-width at half-maximum (FWHM), detection accuracy, quality factor, and sensitivity due to the hybrid TiO₂, Ni, and BP layers. The impact of copper thickness is also thoroughly investigated. The study identifies optimal sensor performance with a sensitivity of 518°/RIU and a quality factor of 91.51/RIU, achieved with optimized thicknesses of 35 nm (Cu), 2 × 4 nm (TiO₂), 10 nm (Ni), and 0.53 nm (BP). Furthermore, an alternative configuration yields even higher sensitivity, achieving 526°/RIU and a quality factor of 96.51/RIU, with a copper thickness of 35 nm, TiO₂ thickness of 2 × 2 nm, and nickel thickness of 15 nm. The enhanced sensitivity and performance of the TiO₂, Ni, and BP hybrid layers suggest their promising applicability in diverse biosensing scenarios. This study highlights the potential of this optimized SPR sensor configuration for advanced biosensing applications, owing to its high sensitivity and improved quality factor.