• Colas, Florent

Abstract

For the last decades, Surface Enhanced Raman Scattering (SERS) have been proven a highly sensitive spectroscopy technique and its application have spread in many areas. The electromagnetic enhancement is considered as the main contribution to the overall enhancement process. It is based on near-field enhancement of the electric field through surface plasmon generation. The plasmon mode of nanoparticles depends on the metal, the shape, the size, the substrate, the adhesion layer and the arrangement [1]. Lithographic techniques enable one to accurately control the geometry of the samples [2]. It is then possible to finely optimize these parameters to design of ultra-sensitive sensor. Previous works showed that the period of a regular arrangement of nanoparticles can be a very efficient parameter for tuning the far-field plasmon band [3] through near-field and far-field coupling. In the context of this poster, we will mainly focus on this parameter. Nanocylinders on a periodic square lattice of variable gap distance from 10 to 1000nm will be considered. Their diameters will go from 100 to 200nm. Gold nanoparticles will be considered as this material is stable in aqueous environment and can be easily functionalized. The substrate will be a classical borosilicate glass (BK7) and the adhesion layer a 2-nm-thick chromium film. We will consider cylinders of 50nm-height. In the context of this poster, we will show results of near-field and far-field calculations with Discrete Dipole Approximation (DDA) using DDSCAT 7.3 [4]. They will be compared to extinction spectroscopy and SERS measurements data in some particular the cases.

Topics

• nanoparticle
• impedance spectroscopy
• surface
• chromium
• glass
• glass
• gold