Layered Gold and Titanium Dioxide Substrates for Improved Surface Enhanced Raman Spectroscopic Sensing

Area of Science:

• Nanotechnology
• Materials Science
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful analytical technique.
• Existing SERS substrates often rely on silver, which can have stability limitations.
• Developing robust and efficient gold-based SERS substrates is highly desirable.

Purpose of the Study:

• To describe a simple fabrication process for multi-layered gold SERS substrates.
• To characterize the performance and stability of these novel substrates.
• To investigate the impact of dielectric spacer layers on SERS enhancement.

Main Methods:

• Fabrication of gold multi-layered substrates using atomic layer deposition (ALD).
• Utilized titanium dioxide (TiO2) as the dielectric spacer material.
• Characterized substrate performance by varying TiO2 spacer layer thickness.

Main Results:

• Achieved multi-layer enhancement factors of 2.3-fold per spacer layer.
• Demonstrated the importance of thin, contiguous dielectric spacer layers for optimal enhancement.
• Substrates showed usable lifetimes exceeding five months under ambient conditions.

Conclusions:

• ALD-fabricated gold multi-layered substrates provide significant SERS enhancement comparable to silver-based systems.
• The process allows for tunable enhancement through control of spacer layer thickness.
• These substrates offer improved stability and shelf life, with potential for regeneration.