Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a Novel SERS Sensing Platform

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Conventional surface-enhanced Raman spectroscopy (SERS) substrates face challenges in achieving reliable, uniform, and reproducible performance due to material inhomogeneity and random resonator geometries.
• These limitations lead to signal inconsistencies, hindering sensitive and comparative analyses.

Purpose of the Study:

• To develop an innovative SERS substrate using monocrystalline gold flakes and a double-wire grating substrate (DWGS) geometry for enhanced signal and reproducibility.
• To address limitations of conventional SERS substrates by minimizing absorption losses and ensuring shape fidelity during nanofabrication.

Main Methods:

• Fabrication of well-defined plasmonic double-wire resonators using monocrystalline gold flakes and focused ion-beam lithography.
• Evolutionary optimization of the DWGS geometry to enhance both excitation and emission processes for maximized SERS signal.

Main Results:

• The developed DWGS demonstrated excellent reproducibility (RSD = 6.6%), repeatability (RSD = 5.6%), and large-area homogeneity (>10^4 µm²).
• Achieved sensitive SERS enhancement for sub-monolayer detection of 4-Aminothiophenol, with demonstrated reusability and long-term stability.
• Validated performance with diverse analytes, including biological macromolecules, confirming sensitive and reproducible detection.

Conclusions:

• The DWGS platform offers a significant advancement over conventional SERS substrates, providing reliable and quantifiable performance.
• Its high reproducibility, sensitivity, and stability make it a promising tool for various sensing applications.