On-Chip Hydrogen Sulfide Detection Using Silicon Carbide Hybrid Plasmonic Slot Waveguide

In this work, a hybrid plasmonic slot waveguide sensor based on silicon carbide (SiC) is studied for the detection of hydrogen sulfide (H2S). The design comprises a metal-dielectric-semiconductor structure. The high refractive index SiC, and a low refractive index SiO2slot are used as the sensor's active detection zone, and augmented with copper to improve electrical field confinement. The use of a hybrid configuration allows for tight localized electromagnetic fields that occur below the diffraction limit within the SiO2slot. Finite element modeling with COMSOL Multiphysics supports the propagation of continuous waves, as well as the broadband modulation of transmitted light. The sensitivity to determine refractive index changes due to the presence of hydrogen sulfide has been calculated, and maximum sensitivities of 517.24 nm/RIU have been observed. The unique properties of SiC, including high-temperature strength, chemical stability, and mechanical resistance, provide a compact and highly sensitive solution for integrated photonic applications used in gas detection.