Design of Ag/TiO₂/Ag Composite Nano-Array Structure with Adjustable SERS-Activity

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Fabricating large-area, controllable surface-enhanced Raman scattering (SERS) active nanostructure substrates is crucial for nanodevice development.
• Existing methods face challenges in scalability and precise structural control for optimal SERS performance.

Purpose of the Study:

• To develop a novel method for fabricating large-area, controllable SERS-active nanostructure substrates with tunable properties.
• To enhance SERS activity by combining silver (Ag) and titanium dioxide (TiO2) in an evolvable composite structure.

Main Methods:

• Combined nano-etching and magnetron sputtering technologies on self-assembled 200 nm polystyrene (PS) colloidal sphere arrays.
• Utilized shadow effects during deposition and plasma etching to create adjustable nanostructures (nano-cap, nano cap-star, nano particle-disk).
• Incorporated Ag/TiO2/Ag composites into the nanostructure arrays to leverage plasmonic and electron transfer properties.

Main Results:

• Successfully fabricated Ag/TiO2/Ag nanostructure arrays with evolvable structures (NC, NCS, NPD) over a large area.
• Demonstrated tunable optical plasmon resonance and reconstructed SERS hotspots due to the nanostructure's rough surfaces and evolutionary designs.
• Observed enhanced SERS activity attributed to the synergistic effects of Ag, TiO2, and TiO2's inherent electron transfer characteristics.

Conclusions:

• The combined nano-etching and sputtering approach provides a scalable method for producing tunable SERS substrates.
• The developed Ag/TiO2/Ag nanostructure arrays exhibit significant potential for applications in chemical detection, surface science, and nanophotonics.
• The ability to regulate plasmon resonance and SERS hotspots offers new avenues for sensitive analytical techniques.