Effect of Percolation on Electrical Conductivity in a Carbon Nanotube-Based Film Radiation Sensor

Devices based on carbon nanotube (CNT) films offer advantages over devices based on single CNT due to their ease of manufacture, good reproducibility, and high efficiency. A good understanding on percolation properties of CNT films is essential in the design of CNT-based film devices. In this paper, the effect of percolation on electrical conductivity in a CNT-based film radiation sensor was studied. CNT films with different densities were prepared to find the relationship between the film conductivity and the CNT density in the film. The effect of CNTs´ length on the critical density of the film was also discussed based on percolation theory. The average length of CNTs determines the critical density of the film and in turn governs the film conductivity. For the CNT-based film radiation sensor, larger responses were achieved when the CNT film was prepared with 3 layers of CNTs. In general, it is expected that by using the unique properties of CNT films within the percolation region, devices based on such films can achieve superior performances.