Temperature Dependence of Conductivity in Composite Film of Single-Walled Carbon Nanotubes with Graphene Oxide

Abstract

The results of low-temperature studies (5–291 K) of conductivity in the composite film of graphene oxide (GO) with single-walled nanotubes (SWNTs) are presented. The composite film was obtained by vacuum filtration of aqueous suspension containing both GO and SWNTs. It was shown that conductivity of composite is largely conditioned by the nanotubes, while graphene oxide film obtained similarly demonstrated no conductivity. Semiconductor behavior with negative temperature coefficient of conductivity was revealed for both composite and nanotube films. Further analysis confirmed that conductivity in the range of 5–240 K is well described within the framework of the 3D Mott model. The conductivity mechanism involves thermoactivated tunneling of electrons through barriers with a variable range hopping (VRH), which is common for disordered semiconductors. At higher temperatures (T > 240 K) the Arrhenius model was used. Such parameters as distance and energy of electron hopping as well as energy barriers were estimated.