Free space material characterization of carbon nanotube thin films at sub-terahertz frequencies

Abstract

A free space, non-destructive, vectorial continuous wave terahertz analysis method is employed to study the material properties of single-walled and multi-walled carbon nanotube thin films deposited on substrates of fused quartz and silicon. The electrical and optical properties of the thin films have been investigated using a vector network analyzer, in the frequency range of 220–325 GHz (WR 3.4) and 325–500 GHz (WR 2.2). The Nicolson–Ross–Weir method is used to extract the material parameters. The refractive index, absorption coefficient, and the complex conductivity of the single-walled and multi-walled carbon nanotube thin films are extracted and studied.

Keywords:

• Continuous wave terahertz
• vector network analyzer
• carbon nanotubes
• refractive index
• absorption
• conductivity

Acknowledgements

This work was supported by the project MITEPHO (MIcrowave and TErahertz PHOtonics, ITN-FP7, 238393) under the European Commission, which seeks to investigate and develop compact and integrated tunable dual-mode diode lasers for THz spectroscopy in sensing, nanotechnology, and biomedical applications.