  The non-linear length-dependent resistance, $\mathcal{R}(l)$ observed in
single-wall Carbon nanotubes (SNTs) is explained through the recently proposed
ionization energy ($E_I$) based Fermi-Dirac statistics ($i$FDS). The length
here corresponds to the Carbon atoms number ($\mathcal{N}$) along the SNT. It
is also shown that $\mathcal{R}_y(l_y)$ $<$ $\mathcal{R}_x(l_x)$ is associated
with $E_I^y$ $<$ $E_I^x$, which can be attributed to different semiconducting
properties in their respective $y$ and $x$ directions.
