Surface-enhanced Raman scattering on periodic metal nanotips with tunable sharpness.
This paper reports on a scalable bottom-up technology for producing periodic gold nanotips with tunable sharpness as surface-enhanced Raman scattering (SERS) substrates. Inverted silicon pyramidal pits, which are templated from non-close-packed colloidal crystals prepared by a spin-coating technology, are used as structural templates to replicate arrays of polymer nanopyramids with nanoscale sharp tips. The deposition of a thin layer of gold on the polymer nanopyramids leads to the formation of SERS-active substrates with a high enhancement factor (up to 10(8)). The thickness of the deposited metal determines the sharpness of the nanotips and the resulting Raman enhancement factor. Finite-element electromagnetic modeling shows that the nanotips can significantly enhance the local electromagnetic field and the sharpness of nanotips greatly affects the SERS enhancement.
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
Nicholas C
NC
Linn
Chih-Hung
CH
Sun
Ajay
A
Arya
Peng
P
Jiang
Bin
B
Jiang
D000465:Algorithms; D003198:Computer Simulation; D055590:Electromagnetic Phenomena; D020342:Finite Element Analysis; D006046:Gold / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
D006046:Gold; D012825:Silicon