Electromigrated nanoscale gaps for surface-enhanced Raman spectroscopy.
Single-molecule detection with chemical specificity is a powerful and much desired tool for biology, chemistry, physics, and sensing technologies. Surface-enhanced spectroscopies enable single-molecule studies, yet reliable substrates of adequate sensitivity are in short supply. We present a simple, scaleable substrate for surface-enhanced Raman spectroscopy (SERS) incorporating nanometer-scale electromigrated gaps between extended electrodes. Molecules in the nanogap active regions exhibit hallmarks of very high Raman sensitivity, including blinking and spectral diffusion. Electrodynamic simulations show plasmonic focusing, giving electromagnetic enhancements approaching those needed for single-molecule SERS.
Ward
Daniel R
DR
Department of Physics and Astronomy, Applied Physics Graduate Program, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
Grady
Nathaniel K
NK
Levin
Carly S
CS
Halas
Naomi J
NJ
Wu
Yanpeng
Y
Nordlander
Peter
P
Natelson
Douglas
D
D036103:Nanotechnology; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties