Polarization- and Wavelength-Dependent Surface-Enhanced Raman Spectroscopy Using Optically Anisotropic Rippled Substrates for Sensing

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Dimitra Gkogkou - , Humboldt University of Berlin, Leibniz-Institut für Analytische Wissenschaften - ISAS, Technical University of Berlin (Author)
  • Benjamin Schreiber - , Helmholtz-Zentrum Dresden-Rossendorf (Author)
  • Timur Shaykhutdinov - , Leibniz-Institut für Analytische Wissenschaften - ISAS (Author)
  • Hoang Khoa Ly - , Technical University of Berlin (Author)
  • Uwe Kuhlmann - , Technical University of Berlin (Author)
  • Ulrich Gernert - , Center for Electron Microscopy (ZELMI) (Author)
  • Stefan Facsko - , Helmholtz-Zentrum Dresden-Rossendorf (Author)
  • Peter Hildebrandt - , Technical University of Berlin (Author)
  • Norbert Esser - , Leibniz-Institut für Analytische Wissenschaften - ISAS (Author)
  • Karsten Hinrichs - , Leibniz-Institut für Analytische Wissenschaften - ISAS (Author)
  • Inez M. Weidinger - , Technical University of Berlin (Author)
  • Thomas W.H. Oates - , Leibniz-Institut für Analytische Wissenschaften - ISAS (Author)

Abstract

Anisotropic Ag nanoparticle arrays were created by metal evaporation on rippled silicon templates for sensing of molecules with surface-enhanced Raman spectroscopy. Our results show that these substrates can be used for analysis of complex molecular mixtures and discrimination of solvent molecules. These properties are due to their polarization and wavelength dependency that provide enhancement in a wide spectral range. The dielectric function parallel and perpendicular to the long axis of the nanostructures was determined via ellipsometry yielding two different plasmonic resonances. Polarized surface-enhanced raman scattering (SERS) was subsequently measured as a function of the polarization angle θ for a 4-mercaptobenzonitrile self-assembled monolayer covalently attached to the Ag surface. For 514 nm excitation a cos2 θ-dependence and for 647 nm excitation a sin2 θ-dependency were found, with the maxima expressing the resonances perpendicular and parallel to the ripples, respectively. Those results open the path for using such a substrate as a chemical sensor providing strong enhancement in a broad range of laser wavelengths on only one sensing surface and increasing the specificity by matching resonant Raman conditions.

Details

Original languageEnglish
Pages (from-to)318-323
Number of pages6
JournalACS sensors
Volume1
Issue number3
Publication statusPublished - 25 Mar 2016
Peer-reviewedYes
Externally publishedYes

Keywords

Keywords

  • 4-mercaptobenzonitrile, anisotropic sensor substrates, chemical sensors, enhancement substrate, polarized SERS, silver nanoparticle arrays