Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a Novel SERS Sensing Platform
A.O. Sweedan1,2, M.J. Pavan1, E. Schatz3, H. Maaß3, A. Tsega4, V. Tzin4, K. Höflich5, P. Mörk6, T. Feichtner6, and M.Y. Bashouti1,2
Published in:
Small, vol. 20, no. 35, pp. 2311937, doi:10.1002/smll.202311937 (2024).
Abstract:
Achieving reliable and quantifiable performance in large-area surface-enhanced Raman spectroscopy (SERS) substrates poses a formidable challenge, demanding signal enhancement while ensuring response uniformity and reproducibility. Conventional SERS substrates often made of inhomogeneous materials with random resonator geometries, resulting in multiple or broadened plasmonic resonances, undesired absorptive losses, and uneven field enhancement. These limitations hamper reproducibility, making it difficult to conduct comparative studies with high sensitivity. This study introduces an innovative approach that addresses these challenges by utilizing monocrystalline gold flakes to fabricate well-defined plasmonic double-wire resonators through focused ion-beam lithography. Inspired by biological strategy, the double-wire grating substrate (DWGS) geometry is evolutionarily optimized to maximize the SERS signal by enhancing both excitation and emission processes. The use of monocrystalline material minimizes absorption losses and ensures shape fidelity during nanofabrication. DWGS demonstrates notable reproducibility (RSD = 6.6%), repeatability (RSD = 5.6%), and large-area homogeneity > 104 µm2. It provides a SERS enhancement for sub-monolayer coverage detection of 4-Aminothiophenol analyte. Furthermore, DWGS demonstrates reusability, long-term stability on the shelf, and sustained analyte signal stability over time. Validation with diverse analytes, across different states of matter, including biological macromolecules, confirms the sensitive and reproducible nature of DWGSs, thereby establishing them as a promising platform for future sensing applications.
1 The Ilse-Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Beer-Sheba Campus, POB 653, Building 51, Be’er Sheva 8410501, Israel
2 Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshset Ben-Gurion, Building 26, Be’er Sheva 8499000, Israel
3 NanoStruct GmbH, Friedrich-Bergius-Ring 15, 97076 Würzburg, Germany
4 French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Be’er Sheva 8499000, Israel
5 Joint Lab Photonic Quantum Technologies, Ferdinand-Braun-Institut gGmbH Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, D-12489 Berlin, Germany
6 Nano-Optics and Biophotonics Group, Experimental Physics 5, Institute of Physics, University of Würzburg, Am Hubland, D-97074 Wurzburg, Germany
Keywords:
double-resonance, focused ion-beam lithography, grating nanostructures, monocrystalline gold flakes, plasmonic resonator, SERS substrate, surface-enhanced Raman spectroscopy
©2024 The Authors. Small published by Wiley-VCH GmbH.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Rightslink® by Copyright Clearance Center
Full version in pdf-format.