Percolation scaling of 1/f noise in single-walled carbon nanotube films

We use Monte Carlo simulations and noise modeling to study the scaling of 1/f noise in single-walled carbon nanotube films as a function of device parameters and film resistivity. Despite its relative simplicity, this computational approach provides a general framework for the characterization of 1/f noise in nanotube films and explains previous experimental observations. We consider noise Sources due to both tube-tube junctions and nanotubes themselves. By comparing the simulation results with the experimental data, we find that the noise generated by tube-tube junctions dominates the total nanotube film 1/f noise. Furthermore, we systematically study the effect of device length and film thickness on the 1/f noise scaling in nanotube films in order to demonstrate that the simulation results are in good agreement with the available experimental data. Our results further show that the 1/f noise amplitude depends strongly on device dimensions, nanotube degree of alignment, and the film resistivity, following a power-law relationship with resistivity near the percolation threshold after properly removing the effect of device dimensions. We also find that the critical exponents associated with the noise-resistivity and noise-device dimension relationships are not universal invariants, but rather depend on the specific parameter that causes the change in the resistivity and 1/f noise, and the values of the other device parameters. Since 1/f noise is a more sensitive measure of percolation than resistivity, these simulations not only. provide important fundamental physical insights into the complex interdependencies associated with percolation transport in nanotube networks and films, but also help us understand and improve the performance of these nanomaterials in potential device applications, such as nanoscale sensors, where noise is an important figure of merit.