The Wavelength-Dependent SERS Template Based on a Nanopillar Array.

Area of Science:

• Nanophotonics and Spectroscopy
• Materials Science

Background:

• Surface-enhanced Raman spectroscopy (SERS) significantly amplifies Raman signals for chemical analysis.
• SERS performance is influenced by template properties, molecular structure, and excitation laser wavelength.

Purpose of the Study:

• To propose and fabricate a simple nanostructured template for SERS.
• To investigate the impact of excitation laser wavelength on SERS signal enhancement.
• To provide a design approach for SERS templates tailored to specific wavelengths.

Main Methods:

• Fabrication of three types of gold nanopillar arrays on silicon wafers.
• Acquisition of SERS signals from Rhodamine 6G (R6G) molecules using blue (458 nm), green (532 nm), and red (633 nm) lasers.
• Optical intensity distribution simulations for different SERS templates and laser excitations.
• Measurement and comparison of enhancement factors (EFs).
• Analysis of photoluminescence spectra and SERS signals using a convolution profile.

Main Results:

• Demonstrated wavelength-dependent SERS enhancement factors on the fabricated nanopillar templates.
• Optical simulations correlated with experimental SERS signal intensities.
• Identified the effectiveness of the nanostructured template even when the laser wavelength is outside the molecule's resonance spectrum.

Conclusions:

• The developed nanostructured template offers a viable platform for SERS applications.
• Understanding wavelength-dependent factors is crucial for optimizing SERS performance.
• This work presents a new strategy for designing SERS templates for diverse excitation wavelengths.