Surface-Enhanced Raman Scattering Based on Sb₂S₃ Microstructures via Femtosecond Laser Direct Writing

The noble-metal-free surface-enhanced Raman scattering (SERS) substrates have gained significant attention due to their abundant sources, signal uniformity, biocompatibility, and chemical stability. However, the lack of controllable synthesis and fabrication methods for high-SERS-activity noble-metal-free substrates hinders their practical applications. In this study, we demonstrate the use of a femtosecond laser direct writing technique to precisely manipulate and modify microstructures, resulting in enhanced SERS signals from Sb₂S₃ nonmetal-oxide semiconductor materials. Compared with unpatterned Sb₂S₃ samples, the Sb₂S₃ microstructures exhibited up to a 16-fold increase in Raman scattering intensity. Interestingly, our results indicate that the femtosecond laser can induce a transformation in the crystalline state of Sb₂S₃ and significantly enhance the Raman spectrum signal within the Sb₂S₃ microstructures. This enhancement is also highly dependent on the period and depth of the microstructures, possibly due to the cavity effects, resulting in a stronger local field enhancement.