1. Collage of Metrology & Measurement Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. National Institute of Metrology, Beijing 100029, China
Abstract:Two Raman tips and their physical preparation methods that can be applied to the tip enhanced Raman spectroscopy (TERS) system are proposed, namely Ag and Ag-plated tips. Based on finite difference time domain (FDTD) simulation, without interlayer and four different interlayer materials, a simulation study of Ag-plated tips with different film thicknesses and Ag tip points with different tips point curvatures is carried out. The influence of the angle between the incident ray and the tip of the tip and the distance between the tip and the sample on the enhancement of the electromagnetic field is explored. The results show that the Ag-plated tip with a thickness of 45nm with titanium and copper as the intermediate layer and the Ag tip with a tip curvature of 55nm have the best electromagnetic field enhancement effect. The angle between the incident light and the tip is 39.27°, and the distance between the tip and the sample is less than 1nm, which has the best electromagnetic field enhancement effect. Based on simulation, magnetron sputtering is used to successfully prepare Ag-plated tips with titanium as the intermediate layer, and focused ion beam (FIB) cutting to successfully prepare Ag tips.
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