银纳米粒子修饰半导体薄膜SERS基底的仿真研究

Simulation study on semiconductor film SERS substrate modified by silver nanoparticles

设计了一种银纳米粒子(Ag NPs)修饰的半导体薄膜锗(Ge)表面增强拉曼散射(SERS)基底。利用时域有限差分(FDTD)方法仿真分析了该SERS基底的消光光谱、局域电场和SERS特性,考察了Ag NPs半径和Ge薄膜厚度对SERS基底拉曼散射信号增强的影响。对比分析了硅(Si)、砷化镓(GaAs)、砷化铟(InAs)和Ge薄膜对SERS基底拉曼散射信号增强的影响。研究发现:Ag NPs半径和半导体介电常数都会影响SERS基底拉曼散射信号的增强。通过计算发现,在半导体薄膜厚度为10 nm时,Ag NPs/Ge薄膜SERS基底在633 nm入射光激发下产生的增强因子(EF)高达7.02×10^(7),对拉曼散射信号的增强作用最佳。

A kind of silver nanoparticles(Ag NPs) modified semiconductor germanium(Ge) film was designed as the surface-enhanced Raman scattering(SERS) substrates.The extinction spectra,local electric fields and SERS properties of the SERS substrates were simulated and analyzed by the finite difference time domain(FDTD) method.The influence of the radius of Ag NPs and the thickness of Ge film on the enhancement of Raman scattering signal of the SERS substrate was discussed.The influence of different film materials including silicon(Si),gallium arsenide(GaAs),indium arsenide(InAs),and Ge film on the enhancement of Raman scattering signal of the SERS substrate was further analyzed.It was found that both the radius of Ag NPs and the dielectric constant of semiconductor had effects on the enhancement of Raman scattering signal of the SERS substrate.It was found that when the semiconductor Ge film thickness was 10 nm,the SERS substrate of Ag NPs/Ge film under the excitation of 633 nm incident light had the high enhancement factor(EF) of 7.02×10^(7),which provided the best enhancement effect on Raman scattering signal.