Numerical Design of a Hybrid SPR Sensor for CO Detection Using Porous Silicon in Kretschmann Configuration

Abstract

In this study, we propose a hybrid surface plasmon resonance (SPR) sensor for detecting carbon monoxide (CO) under the Kretschmann configuration. The proposed structure comprises a BK7 prism, a TiO2 layer, a copper film, three graphene layers, and a porous silicon layer with 80% porosity. Reflectance spectra at 633 nm were simulated using the transfer matrix method. The effective PSi index was determined using the Bruggeman model. The results show a resonance angle shift of 1.3° for an index change of 0.005 RIU. The sensor achieves an angular sensitivity of 130°/RIU, a full width at half maximum (FWHM) of 1.7°, a detection accuracy of 0.58<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°−1</sup>, and a figure of merit of 76.47 RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup>. These performances confirm its potential for real time, label-free, and high-sensitivity CO detection.