1/f Noise in Length Sorted Single-walled Carbon Nanotubes at Their Critical Percolation Conditions

ABSTRACTThe electrical noise characteristics of thin film random networks of single walled carbon nanotubes with lengths of 820nm, 210nm and 130nm, were evaluated in addition to mixed length and pure semiconducting single-walled carbon nanotube networks. This study represents one of the first experimental studies in which highly characterized length sorted single walled nanotubes networks have been investigated to isolate their contributions to 1/f noise. In this work we evaluate the noise power spectrum, in the low frequency range, for each of our type sorted samples and demonstrate the effect of nanotube type, length, dimensionality and critical percolation conditions in 1/f noise generating mechanisms. 1/f noise in two-dimensional (2-D) thin films of random network, homogeneous length sorted SWNTs at their percolation threshold in contrast to three dimensional (3-D) thin films of mixed length SWNT and purely semi-conducting SWNT thin films were investigated. We find that at their respective critical percolation thresholds, xc, length sorted SWNT networks exhibit atypical reduced noise amplitude (A) characteristics compared to their mixed length and semi-conducting nanotube counterparts.