Surface-Enhanced Raman Spectroscopy of Ammonium Nitrate Using Al Structures, Fabricated by Laser Processing of AlN...

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Laser-induced surface structuring is a method for creating functional nanomaterials.
• Aluminum nitride (AlN) ceramics can be processed to form metallic structures.
• Surface-Enhanced Raman Spectroscopy (SERS) requires efficient substrates for trace analyte detection.

Purpose of the Study:

• To investigate laser-induced surface structuring of AlN ceramic.
• To evaluate the fabricated structures as substrates for SERS.
• To determine the detection limit of ammonium nitrate using these SERS substrates.

Main Methods:

• Nanosecond pulsed laser ablation of AlN in air and vacuum.
• Characterization of surface morphology using Scanning Electron Microscopy (SEM).
• Analysis of material composition using X-ray Photoelectron Spectroscopy (XPS).
• Finite Difference Time Domain (FDTD) and Generalized Mie scattering simulations for near-field enhancement and extinction spectra.
• SERS measurements using ammonium nitrate detection at 514 nm and 785 nm excitation wavelengths.

Main Results:

• Laser processing of AlN resulted in the formation of aluminum structures with varying morphologies.
• The fabricated Al structures demonstrated SERS activity, enhancing Raman signals at both 514 nm and 785 nm.
• Higher enhancement was observed for 514 nm excitation.
• The limit of detection for ammonium nitrate was found to be below regulatory limits for drinking water.
• Simulations correlated near-field enhancement with observed SERS efficiency.

Conclusions:

• Laser structuring of AlN is an effective method for fabricating aluminum nanostructures.
• These structures serve as efficient SERS substrates for detecting analytes like ammonium nitrate.
• The developed SERS substrates show promise for sensitive environmental and chemical analysis.