Silver substrates for surface enhanced Raman scattering: Correlation between nanostructure and Raman scattering enhancement

Abstract

The fabrication of substrates for Surface Enhanced Raman Scattering (SERS) applications matching the needs for high sensitive and reproducible sensors remains a major scientific and technological issue. We correlate the morphological parameters of silver (Ag) nanostructured thin films prepared by sputter deposition on flat silicon (Si) substrates with their SERS activity. A maximum enhancement of the SERS signal has been found at the Ag percolation threshold, leading to the detection of thiophenol, a non-resonant Raman probe, at concentrations as low as 10−10M, which corresponds to enhancement factors higher than 7 orders of magnitude. To gain full control over the developed nanostructure, we employed the combination of in-situ time-resolved microfocus Grazing Incidence Small Angle X-ray Scattering with sputter deposition. This enables to achieve a deepened understanding of the different growth regimes of Ag. Thereby an improved tailoring of the thin film nanostructure for SERS applications can be realized.

Pt-Based Nanostructures for Observing Genuine SERS Spectra of p-Aminothiophenol (PATP) Molecules

“…The corresponding selected area electron diffraction (SAED) pattern taken from the area shown in Figure 2a, demonstrates a typical polycrystalline fcc structure with lattice parameter a = 0.38 nm. It is in good agreement with the obtained XRD data, and the lattice fringes of CoPt which were measured to be 0.22 and 0.19 nm, corresponding to the (111) and (200) The genuine SERS spectrum of the 10 −4 mol/L PATP molecules [37] adsorbed on the Pt-based hollow nanostructure surfaces under a laser wavelength of 532 nm is shown in Figure 3a. The emission spectrum of the Pt nanostructure powder was observed with a Raman spectrometer, using a 504 nm wavelength excitation laser as shown in Figure S4.…”

Patterned Diblock Co-Polymer Thin Films as Templates for Advanced Anisotropic Metal Nanostructures

“…10 The related objective is to combine the tunable nanostructure of diblock copolymeric materials 11,12 with the selective interaction of metals with different polymer materials. 13−15 The applications of metallic layers cover catalytically active layers 16 via colloidal contacts 17 or nanostructures for sensor applications 6,18 and single electron devices. 19 Often, spray deposition 17,20 and vacuum deposition methods such as molecular beam epitaxy, 21 vapor deposition, 22,23 and sputter deposition 24,25 are employed to achieve the installation of the metallic layer.…”

Side-to-side alignment of gold nanorods with polarization-free characteristic for highly reproducible surface enhanced Raman scattering

“…1-3 SERS has been researched extensively both theoretically and experimentally. [4][5][6][7] SERS can provide an unprecedented sensitivity resulted from the combination of long-range electromagnetic and short-range chemical enhancements. [8][9][10] However, the SERS analytical application is substantially constrained by the lack of suitable SERS substrates.…”

“…All spectra were calibrated with respect to the silicon Raman mode at 520. 7 was simulated with the finite difference time domain (FDTD) method. The mesh size was 1 nm, and the simulated area was 200 nm  200 nm.…”