Aluminum-Induced Surface-Enhanced Raman Scattering in Ti-Al-Ti Sandwich Multilayer Thin Films

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Localized surface plasmon resonance (LSPR) is crucial for enhancing optical signals.
• Titanium-aluminum (Ti-Al) metal coupling can significantly influence LSPR properties.
• Developing efficient substrates for surface-enhanced Raman scattering (SERS) is vital for sensitive chemical detection.

Purpose of the Study:

• To investigate the effect of Al layer thickness on Ti-Al-Ti sandwich thin films.
• To explore the potential of these films as SERS substrates for methylene blue (MB) detection.
• To understand the mechanisms behind the enhanced Raman scattering signal.

Main Methods:

• Fabrication of Ti-Al-Ti sandwich thin films using magnetron sputtering with varying Al thicknesses.
• Characterization of LSPR properties and electric field enhancement.
• Evaluation of SERS performance using methylene blue as a probe molecule.
• Finite-difference time-domain (FDTD) simulations to complement experimental findings.

Main Results:

• Ti-Al metal coupling within the films strengthened LSPR and created more
• hot-spots
• enhancing the localized electric field.
• A Raman enhancement factor of 3.27 × 10⁶ was achieved for MB detection, surpassing silver thin films.
• A low detection limit of 10^-8 M for MB and excellent substrate uniformity (RSD < 6%) were demonstrated.

Conclusions:

• Ti-Al-Ti sandwich thin films are highly effective SERS substrates due to enhanced LSPR and charge transfer.
• The fabricated substrates offer superior sensitivity, stability, and reproducibility for molecular detection.
• The study validates the potential of nanostructured metal films for advanced sensing applications.