Metal‐dielectric nanostructures for amplified Raman and fluorescence spectroscopy

Abstract

Metal‐dielectric nanostructures are synthesized optimizing their capabilities of enhancing Raman scattering and fluorescence emission. Silver nanoparticles with controlled average size and morphology are obtained by dipping porous silicon (p‐Si) specimens in silver nitrate acqueous solutions. The effects of silvered p‐Si in enhancing Raman Scattering were investigated usinga cyanine dye showing detectable concentration as low as 10‐8M.In order to obtain photoluminescence enhancement, silvered p‐Si samples are coated by ultrathin films of amorphous silicon nitride. The analysis of metal‐dielectric nanostructures show an energy red‐shift of the Surface Plasmon resonances connected to the changes of the dielectrics surrounding the metal particles. In particular, the thickness of such a coating can be tuned in order to enhance the fluorescence emission (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Formation Regularities of Plasmonic Silver Nanostructures on Porous Silicon for Effective Surface-Enhanced Raman Scattering

“…Giorgis’ group has carefully studied a morphology of Ag samples synthesized by the PS immersion in a 1–10 mM AgNO 3 aqueous solution for 0.5–10 min at a temperature of 5–50 °C [ 30 , 37 ]. The strongest Raman enhancement has been observed for the case of an excitation wavelength matching with the SPR band of the Ag/PS substrates.…”

Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon

“…The latter strongly depends on the shape and size of the metallic nanostructures and the gaps between them, while porous silicon template helps to manage these properties. The family of the SERS-active nanostructures formed by metal deposition on porous silicon is very rich and includes metallic nanoparticles [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ] or polydisperse particles [ 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ], dendrites [ 49 , 54 , 83 , 84 ], nanovoids [ 85 ], and metallic oval-shaped NPs [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Figure 2 presents schematic views of plasmonic structures that can be formed with a dependence on porous silicon morphology, doping type, the level of silicon, and the method and conditions of metal deposition.…”

“…It is known that just the silver coating has been formed by the thermal decomposition in porous silicon for the SERS-active substrates. In some works this method has been used as a final step after immersion deposition to provide the complete decomposition of the metal salt inside the pores [ 76 , 92 ].…”

Metal–elastomer nanostructures for tunable SERS and easy microfluidic integration

“…It is worth to underline that beside the NPs morphology, the effect of the dielectric substrate must be taken into account both for the LSP resonance energies and for the elds spatial localization. 28,29 However, the inuence of the different pre-polymer and curing agent ratios used for the synthesis of our PDMS membranes on their refractive index variation can be considered negligible.…”