Wang Tao, Zhang Zhaoshun, Liao Fan, Cai Qian, Li Yanqing, Lee Shuit-Tong, Shao Mingwang
1] Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123, P. R. China [2] Anhui Key Laboratory of Functional Coordination Compounds, Anqing Normal University, Anqing 246011, People's Republic of China.
Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123, P. R. China.
Sci Rep. 2014 Feb 11;4:4052. doi: 10.1038/srep04052.
The finite-difference time-domain (FDTD) method was employed to simulate the electric field distribution for noble metal (Au or Ag)/semiconductor (Ge or Si) substrates. The simulation showed that noble metal/Ge had stronger SERS enhancement than noble metal/Si, which was mainly attributed to the different dielectric constants of semiconductors. In order to verify the simulation, Ag nanoparticles with the diameter of ca. 40 nm were grown on Ge or Si wafer (Ag/Ge or Ag/Si) and employed as surface-enhanced Raman scattering substrates to detect analytes in solution. The experiment demonstrated that both the two substrates exhibited excellent performance in the low concentration detection of Rhodamine 6G. Besides, the enhancement factor (1.3 × 10(9)) and relative standard deviation values (less than 11%) of Ag/Ge substrate were both better than those of Ag/Si (2.9 × 10(7) and less than 15%, respectively), which was consistent with the FDTD simulation. Moreover, Ag nanoparticles were grown in-situ on Ge substrate, which kept the nanoparticles from aggregation in the detection. To data, Ag/Ge substrates showed the best performance for their sensitivity and uniformity among the noble metal/semiconductor ones.
采用时域有限差分（FDTD）方法模拟了贵金属（金或银）/半导体（锗或硅）衬底的电场分布。模拟结果表明，贵金属/锗比贵金属/硅具有更强的表面增强拉曼散射（SERS）增强效果，这主要归因于半导体的介电常数不同。为了验证模拟结果，在锗或硅晶片（Ag/Ge或Ag/Si）上生长了直径约为40 nm的银纳米颗粒，并将其用作表面增强拉曼散射衬底来检测溶液中的分析物。实验表明，这两种衬底在罗丹明6G的低浓度检测中均表现出优异的性能。此外，Ag/Ge衬底的增强因子（1.3×10⁹）和相对标准偏差值（小于11%）均优于Ag/Si（分别为2.9×10⁷和小于15%），这与FDTD模拟结果一致。此外，银纳米颗粒在锗衬底上原位生长，这使得纳米颗粒在检测过程中不会聚集。到目前为止，在贵金属/半导体衬底中，Ag/Ge衬底在灵敏度和均匀性方面表现出最佳性能。
