 Surface-enhanced Raman scattering, SERS, has been widely studied for its potential in chemical and biomedical applications. It relies on the localization of light at metal surfaces, which can be enhanced by plasmonic materials and nanofotonic structures. Plasmonic materials are typically made from metallic nanoparticles or rods, while nanofotonic structures are designed to maximize the localization of light. Hybrid SERS substrates have also been developed by integrating these two technologies. This article was authored by Alan X. Wang and Sian Ming Kong.