Properties Of Multi-walled Nanotubes Research Articles

New Force Field for Simulating Multi-Walled Tubes Based on MoS2

Atomistic model has been proposed to describe the structure, phonon frequencies, and thermodynamic properties of multi-walled nanotubes based on molybdenum disulfide.

Surface state of carbon materials and accumulation of hydrogen in multiwalled carbon nanotubes

Literature data on the nature of oxide structures formed on the surface and in the bulk of carbon materials, including carbon black, multiwalled nanotubes (MWNTs), and carbon fiber are generalized. Positive and negative effects of oxide structures on the properties of MWNTs and the possibilities of their practical utilization are considered. The probable nature of the surface and bulk oxide structures is discussed. The effect of the cathodic polarization value and the nature and composition of the electrolyte on the accumulation of hydrogen in MWNTs directly applied on a steel membrane or involved in an Epoxy-resin-based composite is studied. In an acidic environment (x M HCl + (1 − x) M LiCl), the amount of hydrogen accumulated by carbon nanotubes in a Fe/MWNT system is shown to vary in a range of 3–13.8 wt % and increase with an increase in the acidity of the environment at the cathodic shift of the potential by 0.2 V from the steady-state value (in the absence of external field). In an alkaline environment (1 M KOH), the amount of absorbed hydrogen is 3.5–15 wt % depending on the cathodic polarization (up to 0.4 V) and the weight of multiwalled nanotubes.

Electron beam induced deposition of residual hydrocarbons in the presence of a multiwall carbon nanotube

Amorphous carbon deposited via electron beam induced deposition (EBID) is frequently used to make a low-temperature Ohmic contact with low electrical resistance and improved mechanical characteristics of the multiwall nanotube (MWNT) substrate or MWNT-MWNT interface. However, influence of the MWNT on the EBID process has not been quantified. In this work, we experimentally and theoretically investigate the growth dynamics of EBID of residual hydrocarbons in presence of a MWNT. We demonstrate that the properties of MWNT do not impact amorphous carbon deposition process.

Electron field emitters based on multi-walled carbon nanotubes coated with conducting polymer/metal/metal-oxide composites

The present work describes the field emission properties of multi-walled nanotubes (MWNTs)-based conducting polymer/metal-oxide/metal/MWNTs composites (polyaniline (PANI)/SnO2/Sn/MWNTs). MWNTs were synthesised by chemical vapour deposition technique. SnO2/Sn/MWNTs were prepared by using chemical reduction followed by calcination. By in situ polymerisation method, surface of SnO2/Sn/MWNTs were coated with PANI. PANI/SnO2/Sn/MWNTs field emitters were fabricated over flexible graphitised carbon fabric substrate by spin coating technique. High-resolution transmission electron microscopy and scanning electron microscopy were used to characterise the field emitters. Field emission properties have been studied using an indigenously made facility. The fabricated PANI/SnO2/Sn/MWNTs field emitters exhibited excellent field emission properties with a turn on field of 1.83 V µm−1 and a field enhancement factor of 4800.

Multiwalled Carbon Nanotubes as Building Blocks in Nanoelectronics

Molecular level components, like carbon multiwalled nanotubes (MWNT), show great potential for future nanoelectronics. At low frequencies, only the outermost carbon layer determines the transport properties of the MWNT. Due to the multiwalled structure and large capacitive interlayer coupling, also the inner layers contribute to the conduction at high frequencies. Consequently, the conduction properties of MWNTs are not very far from those of regular conductors with well-defined electrical characteristics. In our work we have experimentally utilized this fact in constructing various nanoelectronic components out of MWNTs, such as single electron transistors (SET), lumped resistors, and transmission lines. We present results on several nanotube samples, grown both using chemical vapor deposition as well as arc-discharge vaporization. Our results show that SET-electrometers with a noise level as low as 6·10 −6 e/ $$\sqrt {Hz} $$ (at 45 Hz) can be built using arc-discharge-grown carbon nanotubes. Moreover, short nanotubes with small contact areas are found to work at 4.2 K with good gate modulation. Reactive ion etching on CVD tubes is employed to produce nearly Ohmic components with a resistance of 200 kΩ over a 2 μm section. At high frequencies, MWNTs work over micron distances as special LC-transmission lines with high impedance, on the order of 5 kΩ.