Multilayer CVD-Graphene and MoS₂ Ethanol Sensing and Characterization Using Kretschmann-Based SPR

The Kretschmann-based surface plasmon resonance (K-SPR) sensor was developed using multilayer graphene and molybdenum disulphide (MoS2) structures on a plasmonic gold (Au) layer for ethanol detection. In this configuration, the SPR spectra of minimum reflectance versus SPR angle was used to determine the sensitivity, detection accuracy and quality factor as the main figure of merit (FOM). Both graphene and MoS2 were used as hybrid detection layers to enhance the ethanol sensing performance using Finite Difference Time Domain (FDTD). The multilayer graphene/Au and MoS2/Au sensors gave a maximum sensitivity of 192.03°/RIU and 153.25°/RIU respectively at 785 nm optical wavelength. In terms of material characterization using the K-SPR technique, chemical vapor deposition (CVD)-grown graphene on Au, had a thickness of 1.17 nm with real and imaginary refractive indices of 2.85, 0.74, and 3.1, 1.19, respectively, at optical wavelengths of 670 nm and 785 nm.