Deposition of silver island film on an optical thin film for surface enhanced Raman scattering

• Main Authors: Yuan-Tai Chang, 張元泰
• Other Authors: Yi-Jun Jen
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/tp264d

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 103 === The localized surface plasmon resonance in the metal nanostructure is generally believed to be the main mechanisms of the SERS enhancement. In this work, optical thin films underneath a silver island film were designed to electric field on the surface. We deposited the Ag mirror and the SiO2 film on the silicon substrate then deposited the silver island films on the surface of SiO2 film. Through this method the surface electric field will be enhanced. The surface morphology of each sample was imaged by SEM. A lot of narrow gaps between the silver islands were observed. The electric field distributions of these silver island films are simulated by the finite difference time domain method and the areal SERS enhancement factor can reach to 104. In the SERS measurement, compared with the silver island films deposited on a bare Si substrate, the silver island films on the optical thin film has stronger SERS signals. The SERS signal was gradually increased with the thickness of SiO2 layer from 50 nm to 150 nm.