Formation of low-resistance ohmic contacts between carbon nanotube and metal electrodes by a rapid thermal annealing method

Abstract

The contact resistance between a carbon nanotube and metal electrodes decreases by several orders of magnitude and becomes long-term stable when the nanotube contacted by Ti-Au electrodes was annealed by a rapid thermal annealing method at 600-800 °C for 30 s. The contact resistances of the annealed samples are in the range 0.5-50 kΩ at room temperature, depending on the electrical properties of the nanotube. The short and relatively low-temperature annealing process enables us to make a surface Ti-nanotube contact suitable for electrical measurements. For the samples with relatively low contact resistances (0.5-5 kΩ) at room temperature, the contact resistance remained constant or decreased slightly as the temperature was lowered. Those with a relatively high contact resistance (5-50 kΩ), on the other hand, showed increasing contact resistance with a lowering of the temperature.

Resistance simulations for junctions of SW and MW carbon nanotubes with various metal substrates

“…There also exists a qualitative compatibility of results obtained for the CNT-Me junctions using both approaches considered in this paper: ( ) first principles 'liquid metal' model and ( ) semi-empirical 'effective bonds' model based on the Landauer relationship. At the same time, the latter results are quantitatively comparable with those measured experimentally, , within the range from several up to 50 kOhm [24]. We have also developed the model of inter-shell interaction for the MW CNTs, which allows us to estimate the transparency coefficient as an indicator of possible 'radial current' losses.…”

Determining the optimal contact length for a metal/multiwalled carbon nanotube interconnect

“…This is hardly the case in reality, as evidence for contamination layers of unspecified origin are often reported. 5 Often, such contamination layers are reduced by activating the contacts by an applied electric field, 6 by rapid thermal annealing, 7 or by current-induced Joule heating. 8 The constriction of injected electrons through localized defects along a nanowire is also possible, resulting in many parallel Sharvin-like points of contact between a metal film and a nanowire.…”

High Temperature SAW wireless sensors based on YCOB and Langasite

“…The stable temperature characteristic of the SAW device is because of the stable YCOB piezoelectric substrate, Au-Ti electrodes and the annealing procedure before measurements. Au-Ti thin film electrodes are widely used for high temperature sensors for their excellent oxidation resistance and outstanding electrical properties [12]. The annealing process have eliminated to voids in electrodes and released residual stresses in the substrates, thus improve the thermal stability of electrodes.…”