Graphene-Ag Hybrids on Laser-Textured Si Surface for SERS Detection

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is crucial for detecting trace species.
• Silver nanostructures are common SERS substrates but suffer from poor chemical stability.
• Developing stable and sensitive SERS substrates is essential for practical applications.

Purpose of the Study:

• To develop a stable and sensitive SERS substrate using graphene/silver film/laser-textured silicon (G/Ag/LTSi) hybrid structures.
• To explore a simple, rapid, and low-cost fabrication method for this substrate.
• To evaluate the SERS performance and stability of the developed substrate.

Main Methods:

• Fabrication of G/Ag/LTSi substrate via laser ablation and silver film coating.
• Transfer of a monolayer graphene film onto the silver-coated surface.
• Investigation of SERS behavior using R6G and 4-MBT molecules as analytes.
• Assessment of substrate stability under ambient conditions over 50 days.

Main Results:

• The G/Ag/LTSi substrate achieved a maximum enhancement factor exceeding 10⁷.
• SERS signal loss was less than 23% after 50 days of exposure to ambient conditions.
• The graphene layer significantly enhanced Raman signals and protected silver nanostructures from oxidation.
• Laser ablation effectively created nanoparticle hotspots on the silicon surface.

Conclusions:

• The G/Ag/LTSi hybrid structure provides a stable and highly sensitive SERS substrate.
• The developed fabrication approach is simple, rapid, and cost-effective.
• This strategy offers a promising route for large-area graphene-silver plasmonic hybrid fabrication for SERS applications.