We propose a catalytic growth mechanism of single-wall carbon nanotubes based on density functional total energy calculations. Our results indicate nanotubes with an “armchair” edge to be energetically favored over “zigzag” nanotubes. We also suggest that highly mobile Ni catalyst atoms adsorb at the growing edge of the nanotube, where they catalyze the continuing assembly of hexagons from carb...

Examples of progress in fabricating branched multi-terminal multi-wall and single-wall carbon nanotube junctions as predicted by nanotechnology simulations, using template growth and nanowelding techniques, respectively, have been briefly reviewed in this report. It is argued that similar general progress in computational nanotechnologydriven fabrication of applications in other nanomaterials s...

This paper investigates the effective wall thickness of a single-walled carbon nanotube, a critical quantity for any research in mechanics and property characterization of carbon nanotubes. To this end, the response of a bundle of single-walled carbon nanotubes to external hydrostatic pressure was modeled using the ring theory of continuum mechanics. The model predicted that the equivalent thic...

Nanoparticles confined in small volumes exhibit functional properties different from that of the bulk material. Furthermore, the smaller the volume available then the greater the effects of confinement are observed to be. Metallic nanoparticles encapsulated within carbon nanotubes have been proposed for many applications ranging from catalysis to quantum storage devices. In this study we examin...

Pb(Zr0.52Ti0.48)O3 (PZT) nanotubes with diameters of 80–100 nm and a wall thickness of 15–20 nm were prepared by sol–gel template technique and using multi-walled carbon nanotubes (MWCNT) as sacrificial templates. The coating process of MWCNT with PZT precursor sol and removal of the carbon nanotubes by an interrupt heat treatment were discussed and studied by Raman spectroscopy. Simultaneous t...

We present a new process to get in-situ-growth carbon nanotubes (CNTs) array device with good FE properties by CO2-assisted thermal chemical vapor deposition (CVD). Field Emission measurement shows that introducing CO2 into CNTs growth system leads to a significant enhancement in the emission properties, both the turn-on field and threshold field decrease. Raman, SEM and TEM investigation resul...

Carbon nanotube sheets have great potential for specific engineering applications owing to their unique, tunable properties such as conductivity. To date, most CNT sheet materials (e.g., buckypapers) are fabricated by using single wall carbon nanotubes (SWNTs). However, multi-wall carbon nanotubes (MWNTs) are much cheaper than SWNTs, and better suited to large scale industrial applications. One...

Using C2H2, 112 and As gases at 550'C, carbon nanotubes were fabricated on the surfaces of twosubstrates coated by nano thin layers of metal catalysts by DC magnetron sputtering. AYStamless steel andFe/CteAl, by thermal chemical vapor deposition (TCVD) The surface properties of the substrates wereparticularly investigated, and the effect of treatment of the substrates on the CNT's growth is cri...

Recent conductance measurements on multi-wall carbon nanotubes (CNTs) reveal an effective behavior similar to disordered single-wall CNTs. This is due to the fact that electric current flows essentially through the outermost shell and is strongly influenced by inhomogeneous electrostatic potential coming from the inner tubes. Here, we present theoretical studies of spin-dependent transport thro...