Density effect of gold nanodisks on the SERS intensity for a highly sensitive detection of chemical molecules

Abstract

International audienceSurface-enhanced Raman scattering (SERS) is a sensitive and widely used as spectroscopic technique for chemical and biological structure analysis. One of the keys to increase the sensitivity of SERS sensors is to use nanoparticles/nanostructures. Here, we report on the density effect of gold nanodisks on SERS intensity for a highly sensitive detection of chemical molecules. Various densities of gold nanodisks with a height of 30 nm on gold/glass substrate were fabricated by electron beam lithography in order to have a good uniformity and reproducibility. The evolution of the enhancement factor (EF) with nanodisk density was quantified and compared to numerical calculations. An EF as high as 2:6 Â 10 7 was measured for the nanodisk with a diameter of 110 nm and a periodicity of 150 nm which corresponds to the highest density (42.2 %)

Plasmonic Enhancement by a Continuous Gold Underlayer: Application to SERS Sensing

“…EFs increase from 633 nm to 785 nm by a factor around 10, which is in good agreement with previous results showing the importance of the excitation wavelength as function of the diameter [44] for disks. A further optimization of the optical response could be done by replacing the titanium adhesive layer by 3-mercaptopropyl-trimethoxysilane (MPTMS) in order to reduce the optical damping [45] where a gain around 10 is obtain in replacement of the chrome (also used as adhesive layer for gold on glass) by MPTMS, by increase the thickness of gold layer or by reducing the gap between nanostructures to obtain zones of stronger EM fields [46].…”

Laser-Fabricated Plasmonic Nanostructures for Surface-Enhanced Raman Spectroscopy of Bacteria Quorum Sensing Molecules

“…With an SERS intensity 36 times higher than that of the normal intensity, the EF was calculated to be 9.27×10 5 . Although this result seems minimal when compared to EFs reported using gold nanodisks [25] or nanopillar arrays [24], these fabrication techniques can be expensive and time-consuming. Alternatively, the laser deposition technique offers a straightforward and cost-effective method to produce noble metal nanostructures with useful SERS efficiencies.…”

“…Thiophenol has been widely used to evaluate the EF of noble metal nanomaterials due to its simple chemical structures and strong affinity to noble metal surfaces [22–25]. This affinity enables the formation of a stable self-assembled monolayer advantageous to the precise measurement of the surface’s EF.…”

Soft nanoimprint lithography on SiO2 sol-gel to elaborate sensitive substrates for SERS detection

“…The order of magnitude of 10 6 agrees with characterization of gold nanostructures functionalized on gold film. 8,9 SERS measurements have also been performed for 400 nm period nanodisks and shown due to collapse effect lower peak intensities.…”

“…5,6 Sample design used in this work with thin gold film under nanostructures has been already reported for his interest in SERS and Surface Plasmon Resonance Imaging (SPRI). [7][8][9] To pattern such device two kinds of lithographic processes can be used. The first one, referenced as conventional like electron beam lithography (EBL) requires long writing times for large areas and a significant cost for large sample productions.…”