Highly Sensitive and Stable SERS Substrate Fabricated by Co-sputtering and Atomic Layer Deposition

Guilin Yin,Shiheng Bai,Dannong He,Zheng Li,Jing Lu,Yanpeng Zhang,Weiming Wang,Xinglong Tu

doi:10.1186/s11671-019-2997-8

Abstract

In this study, we develop a facile method to fabricate highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate, which is realized by combining co-sputtering with atomic layer deposition technology. To accomplish the SERS substrate preparation, we firstly utilized co-sputtering silver and aluminum on glass slides to form uniform discontinuous Ag film by removing Al later, which acted as SERS active moiety and presented high sensitivity in glycerin detection. After coating an ultrathin TiO2 layer via atomic layer deposition (ALD), the samples could further enhance the Raman signal due to the chemical effect as well as the long-range effect of the enhanced electromagnetic field generated by the encapsulated Ag nanoparticles (NPs). Besides, the coated sample could maintain the significant enhancement in air condition for more than 30 days. The high stability is induced by TiO2 layer, which efficiently prevents Ag NPs from surface oxidation. This highly sensitive and stable SERS substrate might highlight the application of interface state investigation for exploring novel liquid lubricating materials.

Highlights

Since surface-enhanced Raman scattering (SERS) was firstly reported [1], it has attracted lots of interests in detecting various analytes at extremely low concentrations due to some excellent characters such as high sensitivity, quick response, noninvasive analysis, and fingerprint recognition [2–5]
An ultrathin TiO2 layer was coated to the Ag NP surface without pretreatment via atomic layer deposition (ALD)
By modulating both sputtering and power ratio during the co-sputtering process, well-distributed Ag NPs on glass slides were obtained as SERS active moiety, which presented highly sensitive SERS performance

Summary

Introduction

Since surface-enhanced Raman scattering (SERS) was firstly reported [1], it has attracted lots of interests in detecting various analytes at extremely low concentrations due to some excellent characters such as high sensitivity, quick response, noninvasive analysis, and fingerprint recognition [2–5]. Different materials have been explored as active SERS species, including Au, Ag, Cu, Pt, and so on [8–11]. There are few reports about Ag nanostructure-based SERS substrate for interface research applied in super lubricating liquids, for challenges such as complex and costly fabrication process, easy aggregation, and rapid surface oxidation when exposed to ambient conditions. These would result in SERS activity loss of the substrate in a short time [23]. The humidity rate of liquid super lubricate will quickly decay of the Raman signal enhancement, influencing the interface state analysis during the friction process [24, 25]

Methods

Results

Conclusion