Low frequency noise spectroscopy of multi-walled carbon nanotubes composites

Resistivity and low frequency (10 Hz - 20 kHz) noise characteristics of composite materials with multi-walled carbon nanotubes (MWCNTs) have been carried out over wide voltage and temperature (73-380 K) ranges. Composite materials with epoxy-grafted (MWCNT's surface covered by liquid epoxy resin) and amino-grafted (MWCNT's surface covered by polyethylene polyamine) MWCNTs were investigated. Low-frequency noise spectra of investigated materials comprise of 1/f
^α
-type components, what indicates that conduction is caused by Mott's hopping between carbon nanoparticles controlled by charge carrier capture and release processes in localized states between them. MWCNT's surface treatment by polyethylene polyamine leads to the larger density of surface states and at the same time more intensive low frequency fluctuations.