the applied voltage. Yao et al. [9] described the I–V curves over a range of higher
voltages up to Æ5 V and the experimental results obtained on a single-wall nanotube
with a length of approximately 1 mm are shown in Figure 10.16.
Again, as in all cases discussed previously, a nonlinear relationship was observed
between the voltage and current. However, the I–V characteristic was entirely
different to that of multiwall nanotubes since, below approximately 100 mV, the
electrical resistance was constant R 0 . However, beyond a range of approximately
Æ100 mV the resistance R of a single-wall nanotube is described by:
Figure 10.14 Typical I–V characteristic of
multiwall nanotubes according to Poncharal
et al. [7]. The I–V characteristic of graphene
platelets is similar. The graph was calculated
using Eq. (10.10), setting a ¼ 0.5 and
b ¼ 0.25 V
À1 . The characteristic is similar to that
shown in Figure 10.5 for gold nanowires.
Figure 10.15 Electric conductance of multiwall nanotubes according to Poncharal et al. [7]. For
voltages above about 100 mV, the electric conductance follows Eq. (10.9); below that limit the
conductivity has a constant value. Graphene layers show a similar behavior [8].
280j 10 Electrical Properties of Nanoparticles