Using Si/MoS₂ Core-Shell Nanopillar Arrays Enhances SERS Signal

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Molybdenum disulfide (MoS₂), a 2D layered material, has potential as a surface-enhanced Raman scattering (SERS) substrate due to its flat surface.
• Low detection efficiency necessitates nanostructure fabrication for enhanced SERS performance of MoS₂.

Purpose of the Study:

• To fabricate and characterize period-distribution Si/MoS₂ core/shell nanopillar (NP) arrays for SERS applications.
• To evaluate the SERS performance of these novel nanostructures for organic molecule detection.

Main Methods:

• Fabrication of Si/MoS₂ core-shell NP arrays via sulfurization of MoO₃ on Si NP arrays.
• Characterization using scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS).
• Assessment of SERS enhancement for Rhodamine 6G (R6G) molecules.

Main Results:

• Si/MoS₂ core-shell NP arrays demonstrated significantly enhanced SERS signal intensity compared to bare Si and MoS₂ thin films.
• Specific peak signal enhancements of approximately 75-fold and 7-fold were observed at 1361 cm^-1 for R6G.
• The larger surface area of the NP arrays facilitates increased molecule absorption and interaction.

Conclusions:

• Si/MoS₂ core-shell NP arrays are effective SERS substrates with enhanced signal detection capabilities.
• The nanostructure design promotes charge transfer and exciton transitions, leading to improved SERS performance.
• These arrays show promise for applications in sensitive biomedical detection.