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

Abstract

How to fabricate large area controllable surface-enhanced Raman scattering (SERS) active nanostructure substrates has always been one of the important issues in the development of nanostructure devices. In this paper, nano-etching technology and magnetron sputtering technology are combined to prepare nanostructure substrate with evolvable structure, and Ag/TiO2/Ag composites are introduced into the evolvable composite structure. The activity of SERS is further enhanced by the combination of TiO2 and Ag and the electron transfer characteristics of TiO2 itself. Deposition, plasma etching, and transfer are carried out on self-assembled 200 nm polystyrene (PS) colloidal sphere arrays. Due to the shadow effect between colloidal spheres and the size of metal particles introduced by deposition, a series of Ag/TiO2/Ag nanostructure arrays with adjustable nanostructure substrates such as nano-cap (NC), nano cap-star (NCS), and nano particle-disk (NPD) can be obtained. These nanoarrays with rough surfaces and different evolutionary structures can uninterruptedly regulate optical plasmon resonance and reconstruct SERS hotspots over a large range, which has potential application value in surface science, chemical detection, nanometer photonics, and so on.

Keywords

• tunable nanostructures arrays
• Ag film
• TiO₂ film
• nano-sphere etching (NSE)
• hot spots
• surface-enhanced Raman scattering (SERS)