Abstract

Combined contribution of electromagnetic and chemical effects and their synchronous tuning are an effective strategy for constructing semiconductor surface-enhanced Raman scattering (SERS) substrates with ultra-high sensitivity. In this work, a sulfur vacancy-rich MoS₂ flower-like microsphere is successfully prepared for the first time through the combination of morphology regulation and defect engineering strategies, achieving a synchronous contribution of electromagnetic and chemical effects to SERS enhancement. SERS enhancement factor is as high as 2.54 × 10⁸, which represents the highest sensitivity among the currently reported semiconductor SERS-active substrates. The theoretical calculations and experiments elucidate the observed enhancement activity and the synchronous enhancement mechanism of electromagnetic and chemical effects. The unique flower-like structures of MoS₂ can induce Mie resonance by multiple reflection and scattering of incident light in the cavity structure, which realizes a strong electromagnetic enhancement effect. Meanwhile, a high-efficient carrier separation in substrate and a multiple-channel charge transfer mode between substrate and analyte can be achieved by means of abundant surface sulfur-vacancy defects, which provide a strong chemical enhancement effect for target analyte. This work opens up a new idea and perspective for constructing supersensitive semiconductor SERS sensors, ultimately advancing practical application of semiconductor SERS technology.