Disposable gold coated pyramidal SERS sensor on the plastic platform.

Area of Science:

• Plasmonics
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful technique for molecular detection.
• Developing cost-effective and efficient SERS substrates is crucial for widespread application.
• Existing SERS substrates often rely on silicon and complex fabrication methods.

Purpose of the Study:

• To evaluate the suitability of gold-coated pyramid arrays fabricated on plastic for SERS sensing.
• To compare the SERS performance of the novel plastic-based substrate against a benchmark silicon-based substrate.
• To understand the electromagnetic field distribution responsible for SERS enhancement in pyramid structures.

Main Methods:

• Replication of gold-coated pyramid arrays on a plastic substrate using roll-to-roll ultraviolet embossing.
• Fabrication of benchmark inverted pyramid (IV-pyramid) arrays on a silicon substrate.
• SERS measurements using benzenethiol (BTh) as a test molecule.
• Numerical simulations to analyze electromagnetic field confinement.

Main Results:

• The novel plastic-based pyramid array substrate demonstrated up to 11 times higher SERS signal enhancement compared to the benchmark IV-pyramid substrate on plastic.
• Numerical simulations and experimental data indicate that strong electromagnetic fields near the pyramid base, not the tip, are responsible for the enhanced Raman signal.
• The plasmon fields extend up to 200 nm from the sidewalls at the pyramid base, increasing the effective sensing volume.

Conclusions:

• Gold-coated pyramid arrays fabricated on plastic substrates via R2R UV embossing are highly effective for SERS applications.
• The design utilizing pyramid bases for electromagnetic field confinement offers a significant advancement in SERS substrate technology.
• This approach presents a promising route for scalable and cost-effective production of high-performance SERS sensors.