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Surface-enhanced Raman scattering of gold nanowires : role of dipolar and multipolar localized surface plasmons

Marc Lamy de la Chapelle ,  L. Billot ,  M. Lopes ,  A.-S. Grimault ,  A. Vial ,  D. Barchiesi ,  J.-L. Bijeon ,  P.-M. Adam ,  P. Royer 

Laboratoire de Nanotechnologie et d'Instrumentation Optique, Université de Technologie de Troyes, 12 rue Marie Curie, BP 2060, Troyes 10010, France

Abstract

We have studied the Surface-Enhanced Raman Scattering (SERS) of shape controlled metallic nanowires which can act as nano-antenna, designed through electron beam lithography and lift off techniques. We have notably studied the influence of localized surface plasmon resonance (LSPR) on the efficiency of SERS [1,2].

The deposited molecular probe used is the trans-1,2-Bis(4-pyridyl)ethylen (BPE) with two different excitation wavelengths of 632.8 nm and 676 nm. The nanowire lengths vary from 50 nm up to 1 µm (the width and the height of the nanowires is fixed). The observation of the dependence of the Raman enhancement versus the nanowire length is clearly demonstrated and remarkably the enhancement is observed to be maximum for a specific length. Moreover, we have compared our SERS results to the particle LSPR and we have determined that the best enhancement is obtained for a LSPR position close to the Raman wavelength. For such arrays, we also observe the existence of multipolar surface plasmon modes (up to 7th order) and we show clearly that multipolar LSP modes exhibits a stronger efficiency than the first dipolar order in SERS process [2].

Our results support the fact that the optimization of SERS efficiency, relative to the LSPR, strongly depends on the shape of the metallic nanoparticles. The enhancement strongly depends on the nanowire parameters which is a crucial point to determine the optical efficiencies of such structure and to optimise the SERS processes.

[1] J. Grand, M. Lamy de la Chapelle, J.-L. Bijeon, P.-M. Adam, A. Vial, and P. Royer, Phys. Rev. B 72, 033407 (2005)

[2] L. Billot, M. Lamy de la Chapelle, A.-S. Grimault, A. Vial, D. Barchiesi, J.-L. Bijeon, P.-M. Adam and P. Royer, Chem. Phys. Lett. 422, 303 (2006)

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2007, Symposium H, by Marc Lamy de la Chapelle
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-25 15:05
Revised:   2009-06-07 00:44