Freestanding and permeable nanoporous gold membranes for surface-enhanced Raman scattering

Abstract

Surface-enhanced Raman spectroscopy (SERS) demands reliable, high enhancement substrates in order to be used in different fields of application. Here, we introduce freestanding porous gold membranes (PAuM) as easy to produce, scalable, mechanically stable, and effective SERS substrates. We fabricate large-scale sub-30 thick PAuM, that form freestanding membranes with varying morphologies depending on the nominal gold thickness. These PAuM are mechanically stable for pressures up to $>3$ bar, and exhibit surface-enhanced Raman scattering with local enhancement factors of $10^4$ to $10^5$, which we demonstrate by wavelength-dependent and spatially resolved Raman measurements using graphene as a local Raman probe. Numerical simulations reveal that the enhancement arises from individual, nanoscale pores in the membrane acting as optical slot antennas. Our PAuM are mechanically stable, provide robust SERS enhancement for excitation power densities up to $10^6$Wcm${}^{-2}$, and may find use as a building block in flow-through sensor applications based on SERS.

arXiv commentRoman M. Wyss and Markus Parzefal contributed equally. Supporting Information included

References in corpus (8)

• Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils
• Raman spectroscopy as a versatile tool for studying the properties of graphene
• Spatially Resolved Raman Spectroscopy of Single- and Few-Layer Graphene
• On the transmission of light through a single rectangular hole
• Interference effect on Raman spectrum of graphene on SiO_2/Si
• High-Field Electrical and Thermal Transport in Suspended Graphene
• Graphene healing mechanisms: A theoretical investigation
• Probing hotspots of plasmon-enhanced Raman scattering by nanomanipulation of carbon nanotubes