# Characterizing unusual metal substrates for gap-mode tip-enhanced Raman spectroscopy

Author(s) Stadler, Johannes, Oswald, Benedikt, Schmid, Thomas, Zenobi, Renato
Publication Type Journal Items, Publication Status: Published
Full Text

## Detailed Information

Title Characterizing unusual metal substrates for gap-mode tip-enhanced Raman spectroscopy
Oswald, Benedikt
Schmid, Thomas
Zenobi, Renato
Journal or Series Title Journal of Raman spectroscopy
Volume Number 44
Issue Number 2
Start Page 227
End Page 233
ISSN 0377-0486
1097-4555
Publisher Wiley
Publication Place Chichester
Publication Date 2013-02
Keyword(s) Tip-enhanced Raman spectroscopy
Plasmonics
Simulations
Finite elements
Finite difference time domain
Abstract In this article, the electromagnetic (EM) field in gap-mode tip-enhanced Raman spectroscopy (TERS) is investigated theoretically and experimentally for a range of commonly used and unusual metal and nonmetal substrates. By approaching a metal tip to a substrate, both form a coupled system that confines the EM field created at the tip apex. The influence of the substrate onto the EM field enhancement is observed in a top-illumination gap-mode TERS setup for different metal substrates. These include Au, the most commonly used substrate, and also a wide range of rarely or previously unused TERS substrates (Cu, Ag, Al, Pd, Pt, Ni, Ti, Mo, W, stainless steel, Al2O3, SiO2). Self-assembled monolayers of thiols and brilliant cresyl blue thin film samples are investigated experimentally on nine metal substrates, all showing considerable TERS enhancement. With finite difference time domain and finite element simulations used, the article provides a good estimate of the EM field enhancement for a wide range of substrates for users to estimate how well a substrate of choice will perform in a gap-mode TERS experiment. The reduction in EM field strength vertical bar E2 vertical bar compared with Au is less than an order of magnitude for many metals (Calculations: Cu 92%, Ag 81%, Ni 53%). This article experimentally shows that a wide variety of conductive substrates can be used, when one is willing to trade a fraction of the EM field enhancement. TERS was seen on all metal substrates including stainless steel, yet quantification was not always possible. These qualitative results were complemented with intensities from calculations. The wider variety of substrates will increase the applicability of TERS and evolve it one step further towards use in standard analytics.
DOI 10.1002/jrs.4169
Additional Notes Received 23 March 2012, Revised 6 June 2012, Accepted 13 July 2012, Published online 21 November 2012
Document Type Article
Publication Status Published
Language English
Assigned Organisational Unit(s) 03430
Organisational Unit(s)
NEBIS System Number 000027994
Source Database ID WOS-000313993300010
Description File Name MIME Type Size
No details could be found
 There are no links available for this record.
 This record has not been viewed during this period

@article{Stdlr2013,
author = "Stadler, Johannes and Oswald, Benedikt and Schmid, Thomas and Zenobi, Renato",
title = "{C}haracterizing unusual metal substrates for gap-mode tip-enhanced {R}aman spectroscopy",
journal = "Journal of Raman spectroscopy",
year = 2013,
volume = "44",
number = "2",
pages = "227--233",
month = feb,
}


E-Citations record created: Mon, 04 Mar 2013, 11:34:05 CET