Tip-enhanced near-field optical microscopy of carbon nanotubes

Abstract

We review recent experimental studies on single-walled carbon nanotubes on substrates using tip-enhanced near-field optical microscopy (TENOM). High-resolution optical and topographic imaging with sub 15 nm spatial resolution is shown to provide novel insights into the spectroscopic properties of these nanoscale materials. In the case of semiconducting nanotubes, the simultaneous observation of Raman scattering and photoluminescence (PL) is possible, enabling a direct correlation between vibrational and electronic properties on the nanoscale. So far, applications of TENOM have focused on the spectroscopy of localized phonon modes, local band energy renormalizations induced by charge carrier doping, the environmental sensitivity of nanotube PL, and inter-nanotube energy transfer. At the end of this review we discuss the remaining limitations and challenges in this field.

Tip-enhanced Raman spectroscopic imaging of patterned thiol monolayers

“…Tip-enhanced Raman spectroscopy (TERS) has been developed to obtain chemical information with very high spatial resolution [1–4], or chemical information from very few molecules, and in some cases even single molecules [5–7]. The technique uses a metal or metalized AFM/STM tip to confine the laser energy focused by a confocal microscope objective and to act as a “nano-torch” to locally excite molecules underneath it and enhance their Raman signals.…”

Finding a needle in a chemical haystack: tip-enhanced Raman scattering for studying carbon nanotubes mixtures

“…Tip-enhanced Raman scattering (TERS) has emerged as a promising technique that offers both rich chemical information and nanometer spatial resolution. [2][3][4][5][6] The idea of this approach is to probe samples using the surface enhanced Raman effects at the apex of a sharp AFM tip. Nanometer spatial resolution can be achieved by the extreme localised enhancement effect.…”

Fluorescence Imaging on the Nanoscale: Bioimaging Using Near-field Scanning Optical Microscopy

“…56 A number of other examples have reported impressive spatial resolution for imaging single dye molecules or quantum dots deposited on glass substrates and for imaging carbon nanotubes, frequently using an 455 antenna approach with a small metal nanoparticle attached to the end of the tip. 55,57 In one particularly interesting study, Sandoghdar and coworkers examined the effects of the gold nanoparticle diameter and the tip-sample distance on the achievable spatial resolution and fluorescence enhancement using a combination of computational work and imaging of dye molecules embedded in a thin film. These 460 results clearly demonstrated the trade-off between fluorescence enhancement and spatial resolution.…”