Electromagnetic characterization of carbon nanotube films subject to an oxidative treatment at elevated temperature

Electromagnetic characterization of CNT films fabricated by thermal decomposition of SiC has been performed. Purification and/or uncapping treatment conditions at an elevated temperature of 400 degrees C under flowing oxygen or carbon dioxide have been studied. A near field microwave microscope was 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 was proposed to confirm experimental data, which showed poor conductivity of the CNT film as grown but has slight improvement after 40 min treatment.