title: Nanocap array of Au:Ag composite for surface-enhanced Raman scattering.
abstract: We fabricated Au:Ag nanocap arrays by co-sputtering Au and Ag onto two-dimensional polystyrene (PS) colloidal sphere templates in a magnetron sputtering system for the surface-enhanced Raman scattering (SERS) substrate. In contrast to the bilayer Au/Ag, the co-sputtering Au:Ag bimetal array formed the protrusion network of Ag and Au nanoparticles, which contributed to Raman enhancement in the waxberry-like structure. The metal protrusions formed waxberry-like shell in which the PS beads were encapsulated. At the same time, the Au:Ag bimetal arrays exhibit 4-fold more enhancement in the SERS signal intensity of Rhodamine 6G at the 1649cm(-1) than Au/Ag bilayer array, which is ascribed to the plasmon coupling between the nanoparticles of Au and Ag on the sample. When the PS colloidal particle templates were etched by O2-plasma before sputtering process, the nanogaps affected the surface plasmon resonance (SPR), and the optimal gaps between adjacent Au:Ag nanocaps generated even stronger SERS enhancements. This SERS substrate of Au:Ag showed high sensitivity and reproducibility. The EF of Au:Ag nanocap array substrate onto which Rhodamine 6G (R6G) were adsorbed was evaluated as 6.72×10(10).
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China. Electronic address: jhyang1@jlnu.edu.cn.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Cong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Northeast Forestry University, Material Science and Engineering Institute, Harbin 150040, Heilongjiang, PR China.
authors.forename: Jinpeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
authors.forename: Yaxin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China; Key Laboratory of Excited State Physics, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, PR China.
authors.forename: Jinghai
authors.initials: J
authors.lastname: Yang
keywords: Au:Ag nanocap; Local electric-field; Nanogap; Surface-enhanced Raman scattering