High Aspect-Ratio Iridium-Coated Nanopillars for Highly Reproducible Surface-Enhanced Raman Scattering (SERS).

Area of Science:

• Nanotechnology
• Materials Science
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) offers high sensitivity for chemical detection.
• Reproducibility challenges in SERS substrates hinder quantitative measurements.
• Existing gold and silver nanostructures face limitations in uniform SERS response.

Purpose of the Study:

• To develop highly reliable SERS substrates using atomic layer deposition (ALD) grown iridium.
• To investigate the SERS performance of iridium-based nanopillar arrays.
• To demonstrate the potential for quantitative SERS measurements with uniform substrates.

Main Methods:

• Fabrication of periodic arrays of high aspect-ratio iridium nanopillars using ALD.
• Characterization of nanostructure morphology and hot spot distribution.
• Evaluation of SERS enhancement and measurement-to-measurement variability.

Main Results:

• ALD-grown iridium nanopillars form ordered arrays with narrow interpillar gaps (<10 nm).
• Efficient and symmetrically distributed hot spots are observed within the nanopillar gaps.
• Iridium substrates provide SERS enhancement comparable to silver substrates.
• Demonstrated a low measurement-to-measurement variability of 5%.

Conclusions:

• ALD-grown iridium nanopillars are highly reliable SERS substrates.
• The ordered nanostructure design ensures reproducible SERS signals.
• These substrates are suitable for quantitative SERS measurements, overcoming previous limitations.