Semiconductor SERS on Colourful Substrates with Fabry‐Pérot Cavities

Abstract Non‐metallic materials have emerged as a new family of active substrates for surface‐enhanced Raman scattering (SERS), with unique advantages over their metal counterparts. However, owing to their inefficient interaction with the incident wavelength, the Raman enhancement achieved with non‐metallic materials is considerably lower with respect to the metallic ones. Herein, we propose colourful semiconductor‐based SERS substrates for the first time by utilizing a Fabry‐Pérot cavity, which realize a large freedom in manipulating light. Owing to the delicate adjustment of the absorption in terms of both frequency and intensity, resonant absorption can be achieved with a variety of non‐metal SERS substrates, with the sensitivity further enhanced by ≈100 times. As a typical example, by introducing a Fabry‐Pérot‐type substrate fabricated with SiO 2 /Si, a rather low detection limit of 10 −16 M for the SARS‐CoV‐2S protein is achieved on SnS 2 . This study provides a realistic strategy for increasing SERS sensitivity when semiconductors are employed as SERS substrates.