We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave discharge of ammonia. Evidence is supplied through Fourier transform infrared (FTIR) spectroscopy with band assignment aided by computational modeling. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy results also provide supporting evidence of functional groups attached to the surfaces of SWNTs from ammonia plasma.

We study the performance and reliability of carbon nanofiber (CNF) interconnects under high-current stress by examining CNF breakdown for four test configurations, suspended/supported with/without tungsten deposition. The use of W is to improve the CNF-electrode contact. The supported cases show a larger current density just before breakdown than the suspended ones, suggesting an effective heat dissipation to the substrate. The W-deposited contacts reduce the initial total resistance from megaohm range without W to kilo-ohms. High-current stress does not change the total resistance of the test structures with W unlike those without W deposition.

We have exposed single-wall carbon nanotubes (SWCNTs) to microwave-generated N2 plasma with the aim to functionalize the nanotubes. The results strongly depend on the distance between the discharge source and the sample, since nitrogen atoms generated can be lost due to recombination. No functionalization was observed when this distance was 7.0 cm. At intermediate distances (2.5 cm), the incorporation of nitrogen and oxygen onto the SWCNT was observed, while, at short distances (1 cm), products containing CN were also observed.

To realize nanocarbons in general and carbon nanotube (CNT) in particular as on-chip interconnect materials, the contact resistance stemming from the metal-CNT interface must be well understood and minimized. Understanding the complex mechanisms at the interface can lead to effective contact resistance reduction. In this study, we compile existing published results and understanding for two metal-CNT contact geometries, sidewall or side contact and end contact, and address key performance characteristics which lead to low contact resistance. Side contacts typically result in contact resistances >1 k , whereas end contacts, such as that for as-grown vertically aligned CNTs on a metal underlayer, can be substantially lower. The lower contact resistance for the latter is due largely to strong bonding between edge carbon atoms with atoms on the metal surface, while carrier transport across a side-contacted interface via tunneling is generally associated with high contact resistance. Analyses of high-resolution images of interface nanostructures for various metal-CNT structures, along with their measured electrical characteristics, provide the necessary knowledge for continuous improvements of techniques to reduce contact resistance. Such contact engineering approach is described for both side and end-contacted structures.

Current-induced breakdown is investigated for carbon nanofibers (CNF) for potential interconnect applications. The measured maximum current density in the suspended CNF is inversely proportional to the nanofiber length and is independent of diameter. This relationship can be described with a heat transport model that takes into account Joule heating and heat diffusion along the CNF, assuming that breakdown occurs when and where the temperature reaches a threshold or critical value.