Oxygen plasma induced MoS/MoO heterojunction for high performance SERS application.

Surface-enhanced Raman scattering (SERS) is a non-destructive spectroscopic analysis technique, and it is known for its high sensitivity and specificity in the detection of trace molecules. In this paper, a novel MoS/MoO heterostructure based non-metallic SERS substrate for highly sensitive molecule detection was reported. Experimentally, the MoS/MoO heterojunction was prepared by partially oxidizing the MoS nanosphere into MoO in an oxygen plasma environment (O). It evidenced that the electronic structure and surface properties of the MoS/MoO heterojunction could be adjusted by precisely controlling the oxidation time, thereby optimizing the SERS performance. The SERS performance of the substrate was evaluated by using the Rhodamine 6G (R6G) molecules as Raman reporters. It showed that a limit of quantification as low as 10 M and an enhancement factor (EF) of 8.54 × 10 (R6G@10 M) could be achieved on the optimal SERS substrate with the set oxidizing time to 300 s. Ultimately, the optimal SERS substrate was employed for detecting bright blue dyes. The results demonstrated that the lowest detectable concentration reaches as low as 10 M, fulfilling the requirements for food safety assessment.