Selenium‐Doped Monolayer MoS ₂ for Ultrasensitive Surface‐Enhanced Raman Spectroscopy Detection of Trace Molecules

Surface‐enhanced Raman spectroscopy (SERS) is pivotal for trace‐molecule detection; however, conventional noble‐metal substrates face cost and stability limitations. Two‐dimensional molybdenum disulfide (MoS ₂ ) has emerged as a promising alternative but suffers from inefficient charge transfer. Herein, we developed a vacancy‐compensated Se‐doping strategy for monolayer MoS ₂ via controlled Ar/O ₂ etching and in situ selenization. The resulting 8.0 at% Se‐doped substrate achieved an ultralow detection limit of 10 ⁻¹² M for rhodamine 6G and an enhancement factor of 10 ⁴ , attributed to the enhanced carrier density and interfacial charge transfer. The platform also demonstrates excellent stability, reproducibility, and generality, offering a viable path toward high‐performance semiconductor‐based SERS applications.