Block Copolymer Derived Vertically Coupled Plasmonic Arrays for Surface-Enhanced Raman Spectroscopy.

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for molecular detection.
• Developing efficient and scalable SERS substrates remains a key challenge.
• Plasmonic nanostructures offer significant potential for enhancing Raman signals.

Purpose of the Study:

• To develop a novel SERS sensing template based on gold-covered nanopillars.
• To investigate the factors influencing SERS efficiency, such as pillar height and plasmonic coupling.
• To demonstrate the scalability and cost-effectiveness of the fabrication method.

Main Methods:

• Fabrication of gold-covered nanopillars using block copolymer self-assembly and reactive ion etching.
• Integration of a perforated gold film and a Babinet complementary dot array.
• Characterization of the SERS performance and reproducibility.
• Finite difference time domain (FDTD) simulations to analyze electromagnetic field enhancement.

Main Results:

• Achieved average SERS enhancement factors as high as 10⁷.
• Observed increased SERS efficiency with smaller pillar heights and stronger coupling.
• Demonstrated excellent reproducibility with a relative standard deviation of 8% for Raman intensity.
• Identified plasmonic hot spots through FDTD simulations.

Conclusions:

• The developed gold nanopillar template offers a highly sensitive and reproducible SERS sensing platform.
• The fabrication method is easy, scalable, and cost-effective.
• The study provides insights into optimizing plasmonic nanostructures for enhanced SERS detection.