Comparative Study of Group-IV Materials in SPR Sensors: Silicon as an Optimized Choice for Chemical and Biochemical Sensing

This study presents an optimized high-sensitivity Surface Plasmon Resonance(SPR) sensor based on Group-IV materials integrated with a CaF2 prism in the Kretschmann configuration. The research aims to enhance sensor performance by leveraging the high refractive index and strong plasmonic coupling of Group-IV materials with silver. The proposed structure consists of CaF2/Ag/Group-IVmaterials/Analyte and operates at a wavelength of 633 nm. A systematic opti-mization process identifies silicon with seven layers as the most effective material,achieving a maximum sensitivity of 472◦/RIU, a Figure of Merit (FoM) of 140.89,a Limit of Detection (LoD) of 1.059 × 10−5, and a Full Width at Half Maxi-mum (FWHM) of 3.35 for a refractive index range of 1.331 to 1.336. Compared to conventional SPR sensors, this optimized design exhibits superior plasmonic confinement and reduced damping losses, leading to enhanced sensing accuracy. These findings highlight the sensor’s potential for highly precise chemical and biochemical detection.