Nanosphere Arrays with Controlled Sub-10-nm Gaps as Surface-Enhanced Raman Spectroscopy Substrates

Wang, Hui; Levin, Carly S.; Halas, Naomi J.

doi:10.1021/ja055633y

Cited by 621 publications

(583 citation statements)

References 24 publications

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“…A broad variety of SERS substrates have been fabricated over the past decade, e.g. nanorods 8 , nanocubes 9 , nanostars 10 , various particle arrays [11][12][13][14][15][16] and silver dendrites 17 . Recently electric field (E-field) enhancement factors (EF) above 10 8 to even 10 10 have been reported.…”

Section: Introductionmentioning

confidence: 99%

Wafer-Scale Leaning Silver Nanopillars for Molecular Detection at Ultra-Low Concentrations

Rindzevicius

Schmidt

et al. 2015

J. Phys. Chem. C

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Wafer-scale surface-enhanced Raman scattering (SERS) substrates fabricated using maskless lithography are important for scalable production targets. Large-area, leaning silver-capped silicon nanopillar (Ag NP) structures suitable for SERS molecular detection at extremely low analyte concentrations are investigated. Theoretical results show that isolated Ag NPs essentially support two localized surface plasmon (LSP) modes. The most prominent LSP resonance is observed in the near-infrared region (~800 nm) and can be tuned by changing the diameter of the silicon nanopillars (Si NPs). The corresponding electric field distribution maps indicate that the maximum E-field enhancement is found at the Ag cavity, i.e. the bottom part of the Ag cap. We argue that the plasmon coupling between the resonant Ag cap cavities contributes most to the enhancement of the Raman signal. We experimentally evaluate these findings and show that by exposing Si NPs to an O 2 -plasma the average Ag NP cluster size, and thus the overall inter-pillar coupling, can be systematically reduced. We show that deposition of Cr adhesion layers on Si NPs (>3 nm) introduce plasmon coupling loss to the Ag NP LSP cavity mode that significantly reduces the SERS intensity. Results also show that short exposures to the O 2 -plasma and the use of 1-3 nm Cr adhesion layers are advantageous for reducing the signal background noise from Ag NPs. In addition, influence of the Ag NP height and Ag metal thickness on SERS intensities is investigated and optimal fabrication process parameters are evaluated. Finally, the SERS spectrum from 100 pM of trans-1,2-bis (4-pyridyl) ethylene (BPE) is recorded showing distinct characteristic Raman vibrational modes. The calculated enhancement factor is of the order of 10 8 , and the SERS signal intensity exhibits a standard deviation of around 14% (660 data points) across a 5x5 mm 2 surface area.

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Section: Introductionmentioning

confidence: 99%

Wafer-Scale Leaning Silver Nanopillars for Molecular Detection at Ultra-Low Concentrations

Rindzevicius

Schmidt

et al. 2015

J. Phys. Chem. C

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“…6(b)). 31 A saturated monolayer adsorption of 4-NTP is reached when the concentration of 4-NTP is >100 µM. At the same concentration, as shown in the Fig.…”

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confidence: 72%

Enhancement of surface enhanced Raman scattering activity of Au nanoparticles through the mesostructured metallic nanoparticle arrays

Kuo

Tasi

et al. 2014

APL Materials

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“…For example, metal nanoparticles can be used as structural building blocks to construct more complex objects in a bottom‐up fashion, holding promise for nanoelectronics and nanorobotics applications 32, 33. In addition, gold or silver nanoparticle aggregate system has been proved to be an excellent substrate for surface‐enhanced Raman scattering applications, which provides the ability to significant amplify the Raman signal of nearby target molecules 34, 35. More interestingly, with the development of metal nanoparticle‐based drug delivery systems or mediated hyperthermia, the capability of acoustic manipulation to concentrate metal nanoparticle will offer a completely fresh approach to the treatment of many diseases including cancer.…”

Section: Introductionmentioning

confidence: 99%

Observation of Metal Nanoparticles for Acoustic Manipulation

et al. 2017

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Use of acoustic trapping for the manipulation of objects is invaluable to many applications from cellular subdivision to biological assays. Despite remarkable progress in a wide size range, the precise acoustic manipulation of 0D nanoparticles where all the structural dimensions are much smaller than the acoustic wavelength is still present challenges. This study reports on the observation of metal nanoparticles with different nanostructures for acoustic manipulation. Results for the first time exhibit that the hollow nanostructures play more important factor than size in the nanoscale acoustic manipulation. The acoustic levitation and swarm aggregations of the metal nanoparticles can be easily realized at low energy and clinically acceptable acoustic frequency by hollowing their nanostructures. In addition, the behaviors of swarm aggregations can be flexibly regulated by the applied voltage and frequency. This study anticipates that the strategy based on the unique properties of the metal hollow nanostructures and the manipulation method will be highly desirable for many applications.

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Nanosphere Arrays with Controlled Sub-10-nm Gaps as Surface-Enhanced Raman Spectroscopy Substrates

Cited by 621 publications

References 24 publications

Wafer-Scale Leaning Silver Nanopillars for Molecular Detection at Ultra-Low Concentrations

Wafer-Scale Leaning Silver Nanopillars for Molecular Detection at Ultra-Low Concentrations

Enhancement of surface enhanced Raman scattering activity of Au nanoparticles through the mesostructured metallic nanoparticle arrays

Observation of Metal Nanoparticles for Acoustic Manipulation

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