title: Large-Area Au-Nanoparticle-Functionalized Si Nanorod Arrays for Spatially Uniform Surface-Enhanced Raman Spectroscopy.
abstract: In this study, large-area hexagonal-packed Si nanorod (SiNR) arrays in conjunction with Au nanoparticles (AuNPs) were fabricated for surface-enhanced Raman spectroscopy (SERS). We have achieved ultrasensitive molecular detection with high reproducibility and spatial uniformity. A finite-difference time-domain simulation suggests that a wide range of three-dimensional electric fields are generated along the surfaces of the SiNR array. With the tuning of the gap and diameter of the SiNRs, the produced long decay length (>130 nm) of the enhanced electric field makes the SERS substrate a zero-gap system for ultrasensitive detection of large biomolecules. In the detection of R6G molecules, our SERS system achieved an enhancement factor of >107with a relative standard deviation as small as 3.9-7.2% over 30 points across the substrate. More significantly, the SERS substrate yielded ultrasensitive Raman signals on long amyloid-β fibrils at the single-fibril level, which provides promising potentials for ultrasensitive detection of amyloid aggregates that are related to Alzheimer's disease. Our study demonstrates that the SiNRs functionalized with AuNPs may serve as excellent SERS substrates in chemical and biomedical detection.
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Lin
authors.affiliation: Department of Mechanical Engineering, Materials Science and Engineering Program, and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
authors.forename: Shujie
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
authors.forename: Chongjun
authors.initials: C
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China.
authors.forename: Zuimin
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China.
authors.forename: Zhenyang
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Department of Mechanical Engineering, Materials Science and Engineering Program, and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Yuebing
authors.identifier: 0000-0002-9168-9477
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China.
authors.forename: Xinju
authors.identifier: 0000-0002-6434-4342
authors.initials: X
authors.lastname: Yang
keywords: Au nanoparticles; Aβ detection; Si nanorods; reproducibility; sensitivity; surface-enhanced Raman spectroscopy