title: The effect of dielectric constants on noble metal/semiconductor SERS enhancement: FDTD simulation and experiment validation of Ag/Ge and Ag/Si substrates.
abstract: 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.
authors: 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.
authors: Tao
authors: T
authors: Wang
authors: 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.
authors: Zhaoshun
authors: Z
authors: Zhang
authors: 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.
authors: Fan
authors: F
authors: Liao
authors: 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.
authors: Qian
authors: Q
authors: Cai
authors: 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.
authors: Yanqing
authors: Y
authors: Li
authors: 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.
authors: Shuit-Tong
authors: ST
authors: Lee
authors: 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.
authors: Mingwang
authors: M
authors: Shao