Multilayer enhanced gold film over nanostructure surface-enhanced Raman substrates

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful technique for molecular detection.
• Conventional gold film over nanostructure (GFON) substrates offer stability but limited sensitivity.
• Optimized silver film over nanostructure (SFON) substrates provide high sensitivity but lack long-term stability.

Purpose of the Study:

• To develop novel SERS substrates with enhanced sensitivity and long-term stability.
• To investigate the impact of multilayer structures and dielectric spacers on SERS enhancement.
• To achieve SERS performance comparable to SFON substrates using gold-based materials.

Main Methods:

• Fabrication of multilayer gold SERS substrates by depositing silver oxide islands on GFON, followed by a second gold layer.
• Utilizing silver oxide as a dielectric spacer between gold layers.
• Characterization of SERS enhancement, stability, and uniformity.

Main Results:

• Achieved a 15.3-fold enhancement in SERS signals compared to conventional GFON substrates.
• Demonstrated SERS sensitivity comparable to optimized SFON substrates.
• Exhibited long SERS active shelf-lives (months) with minimal degradation (<5.2% RSD).

Conclusions:

• Novel gold multilayer SERS substrates offer a promising combination of high sensitivity and excellent stability.
• The silver oxide dielectric spacer is crucial for achieving significant SERS signal enhancement.
• These substrates represent a significant advancement for sensitive and stable molecular detection using SERS.