Non-ohmic current–voltage characteristics in single-wall carbon nanotube network

The non-ohmic current–voltage (I–V) characteristics of the single-wall carbon nanotube network were investigated at low temperatures. The temperature dependence of resistivity at low current (I<10 μA) shows non-metallic negative dρ/dT from T=1.4–300 K. Below T<15 K, gradual decreases of resistivity are observed as the applied currents increase, showing significant non-ohmic behavior at high electric field. The I–V curves in the non-ohmic regime can be fitted well by the fluctuation-induced tunneling model, indicating the importance of inter-tubular contacts or inherent energy barriers inside the tubes.