Designing, fabricating, and imaging Raman hot spots
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113
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Contributed by George C. Schatz, July 13, 2006
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↵*L.Q. and S.Z. contributed equally to this work.
Abstract
We have developed a probe of the electromagnetic mechanism of surface-enhanced Raman scattering via Au nanodisk arrays generated by using on-wire lithography. In this approach, disk thickness and interparticle gap are precisely controlled from 5 nm to many micrometers. Confocal Raman microscopy demonstrates that disk thickness and gap play a crucial role in determining surface-enhanced Raman scattering intensities. Theoretical calculations also demonstrate that these results are consistent with the electromagnetic mechanism, including the surprising result that the largest enhancement does not occur for the smallest gaps.
Footnotes
- †To whom correspondence on theoretical work should be addressed. E-mail: schatz{at}chem.northwestern.edu
- ‡To whom correspondence on experimental work should be addressed. E-mail: chadnano{at}northwestern.edu
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Author contributions: G.C.S. and C.A.M. designed research; L.Q., S.Z., C.X., and A.A. performed research; and L.Q., G.C.S., and C.A.M. wrote the paper.
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Conflict of interest statement: No conflicts declared.
- Abbreviations:
- OWL,
- on-wire lithography;
- SERS,
- surface-enhanced Raman scattering;
- MB,
- methylene blue.
- © 2006 by The National Academy of Sciences of the USA
