Cylindrical posts of Ag/SiO₂/Au multi-segment layer patterns for highly efficient surface enhanced Raman scattering

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful technique for sensitive molecular detection.
• Developing highly efficient and reproducible SERS substrates remains a key challenge in analytical chemistry.
• Nanostructured metallic surfaces are crucial for enhancing Raman signals.

Purpose of the Study:

• To fabricate a highly efficient SERS active substrate using Ag/SiO₂/Au multi-segment cylindrical nanopatterns.
• To investigate the role of ordered patterns and interlayer thickness in SERS performance.
• To demonstrate enhanced sensitivity and reproducibility for low-concentration analyte detection.

Main Methods:

• Fabrication of Ag/SiO₂/Au multi-segment cylindrical nanopatterns via soft-nanoimprint lithography.
• SERS measurements using Rhodamine 6G (R6G) as a model analyte.
• Comparative analysis of SERS enhancement factor (EF) with and without a dielectric interlayer.

Main Results:

• The Ag/SiO₂/Au nanopatterns achieved a significant SERS enhancement factor (EF) of ~1.2 x 10⁶.
• This is substantially higher than bimetallic Ag/Au nanopatterns without a dielectric gap (EF ~1.0 x 10⁴).
• Highly ordered patterns and controlled interlayer thickness enhanced sensitivity and reproducibility.

Conclusions:

• The developed multi-segment Ag/SiO₂/Au nanopatterns represent a high-performance SERS substrate.
• Precise control over nanostructure geometry and interlayer distance is critical for optimizing SERS detection.
• This substrate shows great potential for sensitive and reproducible detection of analytes like fluorescent dyes and DNA.