Low-frequency electric noise spectroscopy in different polymer/carbon nanotubes composites

Carbon nanotubes addition to polymer and epoxy material allows to realize a large variety of new types of sensors and actuators. For the development of these devices, a deeper understanding of the basic charge carriers transport mechanisms is needed and low-frequency noise spectroscopy can effectively contribute to this task. The dc and electrical noise characteristics of different polymer/carbon nanotubes composites are analyzed at temperatures from 10 to 300 K. It has been found that a random tunnel junctions resistive networks model describes all the systems under test. A crossover from a two-level tunneling mechanism, at low temperatures, to resistance fluctuations induced by percolative paths, in the high-temperature region, has also been observed. This behavior of the 1/f noise is a general feature of the investigated highly conducting nanocomposites, independent of the specific polymer matrix and nanotube concentration.