High‐resolved surface‐enhanced Raman scattering on Ag@TiO 2 plasmonic nanostructure

Abstract Surface‐enhanced Raman scattering (SERS) is an ultrasensitive spectroscopic analysis technique widely used for molecule detection. However, manufacturing uniform, stable, and ultrasensitive substrates remains a challenge for the practical application of the SERS technology. Precious metals and semiconductors have been proved to be attractive and universal for SERS detection. In this work, a facile strategy is applied to prepare uniform three‐dimensional (3D) Ag@TiO 2 nanostructures as SERS sensors. The Scanning electron microscopy and X‐ray photoelectron spectroscopy results indicate that silver nanoparticles are uniformly deposited into the pores of the TiO 2 nanocavity arrays. The 3D hybrid substrate presents highly sensitive SERS signals of 4‐mercaptobenzoicacid (4‐MBA) with a detection limitation as low as 10 −17 M. To prevent the oxidization of Ag and keep the activity of the film, a polymer mask was deposited on the SERS substrate and brought about excellent stability after weeks of reserving in air. In a nutshell, a SERS substrate with a high sensitivity and stability as well as good uniformity has been successfully developed in this work, which has a potential application for high‐precision SERS detection.