Percolation Effect on the Conductivity of Single-Walled Carbon Nanotube Network

In this paper, we report that the resistance of the SWNT network grown by chemical vapor deposition has a close relationship with the applied current in the range of microampere to milliamperes. At the temperature of 1.5 K, the resistance of SWNT network will decrease with an increasing current. When the applied current is larger than 1 mA, the resistance tends to saturate gradually. At temperature of 100 K, the resistance remains stable and does not depend on the current. The mechanism of this phenomenon is attributed to the series-parallel connection structure of SWNT network, which forms a conducting network with the percolation probability modulated by the applied current. At low temperature, the resistance of the SWNT network will decrease because the percolation probability becomes large with an increasing current. While at high temperature, the percolation probability remains constant due to thermally assisted transfer effect and thus the resistance is not affected by the applied current.