Nanoscale roughness on metal surfaces can increase tip-enhanced Raman scattering by an order of magnitude.
We studied the influence of nanosteps on signal intensity in gap-mode tip-enhanced Raman spectroscopy (TERS). A benzenethiol monolayer adsorbed on an Au substrate was investigated. The correlation between the TERS signal and the local topography on the substrate shows that a 2 nm high sharp step on the Au surface can significantly increase the enhancement. Furthermore, theoretical models were built, and the numerical simulation results were consistent with our experimental results. The findings provide evidence that nanoscale roughness can play a crucial role in the "hot sites" corresponding to single-molecule surface-enhanced Raman spectroscopy (SERS).
Zhang
Weihua
W
Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
Cui
Xudong
X
Yeo
Boon-Siang
BS
Schmid
Thomas
T
Hafner
Christian
C
Zenobi
Renato
R