Gold dimer nanoantenna with slanted gap for tunable LSPR and improved SERS
Di Fabrizio, Enzo M.
Maragó, Onofrio M.
Gucciardi, Pietro Giuseppe
Lamy De La Chapelle, Marc L.
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Physical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
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AbstractWe focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method-taking into account periodicity, adhesion layer, and roughness-is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated. © 2014 American Chemical Society.
SponsorsThe authors thank the Nanoantenna European Project (FP7 Health-F5-2009-241818), the Region Champagne-Ardennes, the Conseil Regional de l'Aube, and MIUR (Project PRIN 2008J858Y7 and Programma Operativo Nazionale Ricerca e Competitivita 2007-2013, PON01_01322 PANREX) for financial support.
PublisherAmerican Chemical Society (ACS)