Recent studies have investigated the photomechanical properties of carbon nanotubes which can be utilized to construct optical actuators. In this paper we compare the photomechanical response from single-wall and multi-wall carbon nanotube/polymer systems in multilayer and nanocomposite actuator constructions. Incorporating polymers in the actuators, single-wall and multi-wall nanotubes show si...

We investigate the nitrogen substitutional impurity in semiconducting zigzag and metallic armchair single-wall carbon nanotubes using ab initio density functional theory. At low concentrations (less than 1 at. %), the defect state in a semiconducting tube becomes spatially localized and develops a flat energy level in the band gap. Such a localized state makes the impurity site chemically and e...

We present preliminary results of Raman scattering measurements of multiwall carbon nanotubes (MWCNT). The nanotubes have been carefully dissolved, separated and then characterized by AFM. The micro-Raman spectra of the objects are taken with 514,5nm wavelength excitations and in the temperature range 4K 400K. Basically the spectra are quite similar to the well known single wall carbon nanotube...

Tunable Raman spectroscopy is used to measure the optical transition energies Eii of individual single wall carbon nanotubes. Eii is observed to shift down in energy by as much as 50 meV, from -160 to 300 degrees C, in contrast with previous measurements performed on nanotubes in alternate environments, which show upshifts and downshifts in Eii with temperature. We determine that electron-phono...

We report a comprehensive theoretical study of structural and electronic properties of substitutional oxygen and zinc contaminations in a model of single wall GaN nanotubes by means of ab initio supercell calculations. Our investigation yields many interesting results. The following ones deserve to be developed. Oxygen forms a shallow donor in the single wall GaN nanotubes as in bulk GaN polyty...

A new and simple strategy for the dispersion of single-wall carbon nanotubes in aqueous media is presented which does not rely on hydrophobic interactions between the polypeptidic dispersing agent and the nanotubes, and allows the surface charge of the resulting conjugate materials to be controlled.

We have carried out momentum-dependent measurements of the density response function of bulk samples of purified single wall nanotubes using electron energy-loss spectroscopy. Carbon nanotubes support both excitations between delocalized and localized electronic states. The p-plasmon exhibits significant q-dependence, with a dispersion relation similar to that of the graphite plane, demonstrati...

The discovery of lower dimensional forms of Carbon with unique mechanical and electronic properties has generated new possibilities in many areas of technology especially in nanotechnology. Recent emergence of some nanoscale device applications show how this potential is turning into a reality. Over the years, we have employed various levels of theory to study the structure and properties of ca...

This paper exploits the chirality-dependent optical properties of single-wall carbon nanotubes for applications in wavelength-selective photodetectors. We demonstrate that thin-film transistors made with networks of carbon nanotubes work effectively as light sensors under laser illumination. Such photoresponse was attributed to photothermal effect instead of photogenerated carriers and the conc...