Broadband Electrical Characterization of Multiwalled Carbon Nanotubes and Contacts

Published

March 22, 2007

Author(s)

Paul Rice, T. M. Wallis, Stephen E. Russek, Pavel Kabos

Abstract

We have welded an individual multiwalled carbon nanotube (MWNT) onto a microlithographically-patterned coplanar waveguide (CPW) and measured the electrical response of the nanotube and the contacts from 100 MHz to 24 GHz. The MWNT was welded to the CPW in the scanning electron microscope using electron beam induced deposition of carbon. A commercial vector network analyzer was used to collect the scattering matrix elements (S11, S12, S21, S22) of the two-port networks. A set of coplanar artifacts was used to determine the propagation constant. With this approach the electrical properties of the CPW up to the welds can be removed from the measurement, providing sensitivity to the properties of the MWNT as well as the contacts. During the measurements, the electronic properties of the MWNT CPW, as welded, showed a pronounced sensitivity to exposure to light. Repeating the welding process on the contacts clearly changed the subsequent electrical properties. We also note that the measurements and model presented here may be used to determine the impedance of the welded MWNT. This simplified model is a first approach and a full ZMWNT impedance matrix may be calculated via more rigorous modeling.

Citation

Nano Letters

Volume

7

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1021/nl062725s

Keywords

carbon nanotubes, high frequency broadband testing, carbon nanotube electrical contacts, coplanar waveguide, thru-reflect-line method, electron beam induced deposition welding

Citation

Rice, P. , Wallis, T. , Russek, S. and Kabos, P. (2007), Broadband Electrical Characterization of Multiwalled Carbon Nanotubes and Contacts, Nano Letters, [online], https://doi.org/10.1021/nl062725s (Accessed October 10, 2025)