Fabrication of nano/microstructures for SERS substrates using an electrochemical method

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Surface-enhanced Raman scattering (SERS) requires substrates with specific nanostructures to amplify weak molecular signals.
• Developing cost-effective and reproducible SERS substrates remains a key challenge in chemical sensing.

Purpose of the Study:

• To fabricate a novel, low-cost SERS substrate using a three-dimensional arrayed nanopore structure on a magnesium (Mg) surface coated with gold (Au).
• To investigate the influence of micro/nanostructure dimensions and gold film thickness on SERS performance.
• To demonstrate the substrate's capability for detecting biomolecules.

Main Methods:

• Fabrication of 3D arrayed nanopore structures on Mg using an electrochemical method.
• Coating the structured Mg surface with a thin gold film to create the SERS substrate.
• Utilizing rhodamine 6G (R6G) as a probe molecule for SERS measurements.
• Characterizing the substrate topography and gold film thickness.

Main Results:

• Optimized electrochemical treatment time (1 min) yielded a five-fold increase in Raman intensity compared to other times.
• Achieved SERS enhancement factors ranging from 10^6 to 1.75 x 10^7.
• Successfully detected a 10^-6 mol/L lysozyme solution, demonstrating high sensitivity.

Conclusions:

• The developed Mg-Au nanopore structure is a promising, low-cost, reproducible, and homogeneous SERS substrate.
• Electrochemical fabrication offers tunable control over nanostructure dimensions for optimized SERS performance.
• This method is suitable for sensitive detection of analytes, including biomolecules.