Large-scale self-organized gold nanostructures with bidirectional plasmon resonances for SERS

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Developing efficient substrates for surface-enhanced Raman spectroscopy (SERS) is crucial for high-throughput applications.
• Current fabrication methods can be time-consuming and costly, hindering widespread adoption.
• There is a need for scalable and tunable plasmonic nanostructures.

Purpose of the Study:

• To develop a facile, wafer-scale fabrication method for self-organized, parallel-oriented plasmonic gold nanostructures.
• To investigate the tunable, bidirectional plasmonic response of these nanostructures.
• To evaluate their performance as SERS substrates for chemical sensing.

Main Methods:

• A two-step fabrication process involving low-energy ion beam irradiation and metal deposition.
• Optical spectroscopy, including localized surface plasmon resonance (LSPR) analysis.
• Spectroscopic ellipsometry and Raman spectroscopy to probe polarization and wavelength dependence.
• Finite element method (FEM) calculations for electromagnetic enhancement analysis.

Main Results:

• Successful fabrication of self-organized, parallel-oriented gold nanostructures.
• Demonstration of independent and tunable bidirectional plasmonic responses.
• Achieved signal amplification with enhancement factors exceeding a thousand.
• FEM calculations confirmed electric field enhancement distribution and hotspot origins.

Conclusions:

• The developed fabrication method is scalable and cost-effective for producing advanced SERS substrates.
• The tunable, bidirectional plasmonic properties make these substrates versatile for various analytes and laser excitations.
• These SERS substrates are highly efficient and suitable for high-throughput chemical sensing applications requiring directionality and stability.