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Plasmonics and single‐molecule detection in evaporated silver‐island films
Author(s) -
Moula G.,
RodriguezOliveros R.,
Albella P.,
SanchezGil J.A.,
Aroca R.F.
Publication year - 2012
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201200149
Subject(s) - plasmon , surface plasmon resonance , materials science , raman scattering , localized surface plasmon , substrate (aquarium) , raman spectroscopy , surface plasmon , resonance (particle physics) , layer (electronics) , molecule , molecular physics , nanotechnology , optoelectronics , optics , nanoparticle , chemistry , atomic physics , physics , oceanography , geology , organic chemistry
The plasmonic origin of surface‐enhanced Raman scattering (SERS) leads to the concept of hotspots and plasmon coupling that can be realized in the interstitial regions, or on specially engineered, silver and gold nanostructures. It is also possible to achieve spatial locations of high local field or hotspots on silver‐island films (SIF) allowing single‐molecule detection (SMD). When a single monomolecular layer coating the SIFs contains dye molecules dispersed in it, single‐molecule impurities, (with an average of one hundred dye molecules in 1 µm 2 , which is the field of view of the micro‐Raman system), SMD is observed as a rare statistical event. Here, the SMD results for silver‐island films are presented, with the same nominal mass thickness, but differing in the localized surface plasmon resonance that is a function of the temperature of substrate during deposition. A blue‐shifted plasmon can be seen as a decrease in plasmon coupling for deposition at higher temperature. A simple two‐particle model for localized plasmon resonance coupling calculations, including the shape and substrate effects seems to explain the trend of observations.