Remarkable Raman Signal Enhancement on Gold-Coated Architecture for Molecular Sensing Applications

Surface-enhanced Raman scattering (SERS) is a highly sensitive and minimally invasive technique for detecting trace-level chemical analytes. Achieving high enhancement factors (EF) depends on precisely engineered sensing architectures made of SERS-active materials and advanced designs that amplify the electric field of incident photons. In this work, we demonstrate a synergistic enhancement arising from the plasmonic effects of gold nanostructures and cavity-enhanced Raman scattering (CERS), resulting in an EF as high as 10⁹. The SERS substrate was fabricated on silicon featuring an array of submicrometer-sized holes coated with gold nanostructures. Raman measurements were performed using 532 nm and 633 nm laser excitations with methylene blue (MB) and crystal violet (CV) as probe molecules. The results will be discussed in light of the underlying Raman enhancement mechanisms. The observed signal amplification demonstrates the strong coupling between plasmonic and cavity effects, paving the way for the development of cost-effective, ultrasensitive SERS platforms for practical sensing applications.