Transparent and flexible networks with randomly distributed single-walled carbon nanotubes (SWCNTs) are emerging as novel materials for various applications, particularly as electronic materials. We investigate the frequency-dependent impedance measurements up to 20 GHz, of single-walled carbon nanotube networks on transparent and flexible substrates, by using two different techniques: two probe and Corbino reflectometry setups. The thickness and roughness of the thin film of SWCNT are examined by AFM. The impedance measurements show the cut-off frequency increases with increasing the density of SWCNT. The log-log plot of low frequency impedance as a function of the cut-off frequency shows the same slope in both measuring techniques. The slope is independent on sample geometries, which is characteristic of a totally disordered system. The cut-off frequencies observed by the Corbino reflectometry technique are 3 orders of magnitude higher than those observed by two-probe technique even for the same SWCNTs density network. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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