Wideband nonlinear characteristics of random multiwalled carbon nanotubes network

ABSTRACT In this work, multiwalled carbon nanotubes (MWCNTs) were randomly deposited in gaps of microstrip interdigitated capacitive (IDC) structure. Measured I‐V characteristics show nonlinear behavior of MWCNTs. Supported by an analytical Schottky‐based model, the nonlinear mechanism is attributed to semiconductor/metallic (S/M) junction properties. Measuring the IDC over a wide frequency band, from 1 kHz up to 3 GHz, we demonstrate there is a maximum frequency (∼10 MHz) beyond which the nonlinear behavior of the MWCNTs network vanishes. An equivalent lumped element circuit for MWCNTs‐based IDC describes well the measured behavior up to 3 GHz. Thanks to the extracted equivalent circuit, we demonstrate that the capacitive couplings between MWCNTs dominate over nonlinear effects above 10 MHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2648–2652, 2013