Probing hotspots of plasmon-enhanced Raman scattering by nanomanipulation of carbon nanotubes

TL;DR

This paper introduces a two-step nanomanipulation method to precisely probe and activate hotspots of plasmon-enhanced Raman scattering in carbon nanotubes using AFM and plasmonic nanodimers.

Contribution

It presents a novel approach combining dielectrophoretic deposition and AFM manipulation to locate and activate Raman hotspots in carbon nanotubes.

Findings

Successful placement of nanotubes in plasmonic hotspots

Observation of plasmon-enhanced Raman scattering activation

Evidence of D-mode activation by near-field effects

Abstract

We present a two-step procedure to probe hotspots of plasmon-enhanced Raman scattering with carbon nanotubes. Dielectrophoretic deposition places a small carbon nanotube bundle on top of plasmonic Au nanodimer. After 'pre-characterising' both the nanotubes and dimer structure, we subsequently use the tip of an AFM to push the bundle into the plasmonic hotspot located in the 25nm wide dimer gap, characterize its location inside the gap, and observe the onset of plasmon-enhanced Raman scattering. Evidence for the activation of the carbon nanotube's double-resonant D-mode by the near-field of the plasmonic hotspot is discussed.