Highly sensitive and scalable AAO-based nano-fibre SERS substrate for sensing application.

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Well-ordered periodic nanostructures are crucial for surface-enhanced Raman spectroscopy (SERS).
• Conventional fabrication methods like electron beam lithography offer high resolution but suffer from low throughput.
• There is a need for scalable and highly sensitive SERS substrates.

Purpose of the Study:

• To develop a highly sensitive and scalable AAO-nano-fibre (ANF) substrate for SERS applications.
• To optimize fabrication parameters for enhanced SERS performance.
• To evaluate the performance of the ANF substrate against existing SERS substrates.

Main Methods:

• Optimizing the second anodisation time during the two-step anodisation of aluminium.
• Performing an additional wet etching step on the resulting anodic aluminium oxide (AAO) substrate.
• Characterizing the SERS performance, including detection limit, signal-to-noise ratio, and enhancement factor.

Main Results:

• The optimized ANF substrate demonstrated superior SERS sensitivity compared to AAO nanoholes and metal-film-on-nanoparticles substrates.
• A low detection limit of 0.1 nM was achieved with a signal-to-noise ratio of 2.6-3 at low excitation power (0.1 mW).
• The ANF substrate exhibited a high enhancement factor of 9.28 × 10^6 with a low standard deviation (≤8%).

Conclusions:

• The optimized ANF substrate offers a significant advancement in SERS technology.
• The high sensitivity, scalability, and reproducibility make ANF a promising candidate for commercial SERS applications.
• This work paves the way for wider adoption of SERS in various fields.