Electromagnetic characterization of carbon nanotube films by a two-point evanescent microwave method

Electromagnetic characterization of carbon nanotube (CNT) films fabricated by thermal decomposition of silicon carbide (SiC) has been performed. A near-field microwave microscope is used to measure the real and imaginary parts of the complex permittivity of CNT films through the frequency shift and the change in reciprocal quality factor between two extreme positions of an evanescent microwave probe tip (in contact with the sample, and away from interaction with it). A theoretical two-point model is proposed to confirm experimental data, which shows poor conductivity of the CNT film. A comparison of our results with existing theoretical models and experimental data is presented.