Defect-induced electrical conductivity increase in individual multiwalled carbon nanotubes

Abstract

The authors demonstrate that ozone exposure of individual multiwalled carbon nanotubes (CNTs) results in up to threefold increase in CNT conductivity and 50% decrease in carrier transport activation energy. Ozone exposure induces bond breaking in the individual shells and promotes cross-shell bridging via sp3 bond formation. Intershell bridging facilitates charge carrier hopping to inner shells, which can serve as additional charge carrier transport pathways, offsetting the effect of defect-scattering-induced conductivity decrease. The CNT etch rate systematically increases with decreasing initial outer diameter and decreases with incremental ozone exposure, which could provide means to controllably tailor the CNT conductance. The results suggest that controlled defect creation could be an attractive strategy to induce electrical conductivity increase in multiwalled CNTs for use in nanodevice wiring and related applications.

Enhanced nucleate boiling on horizontal hydrophobic-hydrophilic carbon nanotube coatings

“…CNTs with defects, which were generally regarded to have mechanical, 14 electrical, 15 and thermal disadvantages, 16 were shown to exhibit intriguing properties for many emerging applications such as nano-sensors, 17 super conductors, 18 catalysts, 19 and field effect transistors. 20 In this study, the hydrophobic-hydrophilic composite interfaces were synthesized by partially oxidizing pristine MWCNT surfaces to form hydrophilic carboxylic and hydroxylic functional groups on the defect sites of MWCNTs.…”

Conductivity of multiwall carbon nanotubes: Role of multiple shells and defects

“…A large defect density increases scattering events and therefore the probability of scattering into a neighboring shell. It was also shown that broken bonds can rearrange with other shells increasing the intershell conductivity [31]. Consequently, it is not completely surprising that the non-local potential is increased compared to samples A-C, indicating a larger amount of current flowing in the inner shells ( fig.…”

“…Intershell connections can also be induced artificially by breaking bonds via ozone exposure. The atoms rearrange creating sp 3 orbitals and cross-link the shells [31]. This may lead to a increased transmission probability between the shells.…”

Imaging of charge trapping in distorted carbon nanotubes by x-ray excited scanning probe microscopy

“…2 In such networks, however, unexpected distortions of CNTs at basic subassemblies such as contacts and branches occasionally occur during fabrication. The local distortions modulate the electronic states of CNTs, [3][4][5] resulting in the discontinuity or degradation of electron transport. Knowledge about the origin and cause of electronic modulation in CNT networks is crucial to realize integrated circuits; however, undesirable electronic modulations cannot be easily detected in the images of CNTs obtained by simple microscopic techniques.…”