Electrical Transport and Magnetoresistance of Single-Wall Carbon Nanotube Layers on Silica Fibers
Qi Lu and Vladimir Samuilov, Department of Physics, St. John’s College of Liberal Arts and Sciences
Robin Helburn, Department of Chemistry, Pace University
V. K. Ksenevich, Department of Physics, Belarus State University
Abstract
The electrical transport properties are the most important for a number of applications of carbon nanotubes, in particular, for sensors development.
This work is focused on single-wall carbon nanotubes (SWCNTs) coatings of silica fibers. The samples under test were produced by means of clinging of pristine SWCNTs dispersed in water to previously silanized silica fibers.
The dependencies of resistance of SWCNTs coatings on temperature R(T) and on magnetic fields R(B) were measured in the temperature range 2 300 K and in magnetic fields up to 8 T. In the low temperature range - up to T~30 K - R(T) dependence can be well fitted by Mott’s law for variable-range hopping . In the temperature range 30 300 K good fitting results give the approximation of R(T) dependence by a typical law for fluctuation-induced tunneling conductivity mechanism. Both negative and positive (inherent for hopping conductivity) magnetoresistance (MR) were observed in the system in the temperature range 2 6 K. As the temperature exceeds 6 K only negative MR was observed in the whole range of the available magnetic fields. The features of carrier transport in SWCNTs coatings of silica fibers are compared with those in single walled carbon nanotube fibers.