Mechanisms of carrier transport in Cux(SiO2)1-x nanocomposites manufactured by ion-beam sputtering with Ar ions

Abstract

The present paper investigates the temperature/frequency dependences of admittance Z in the granular Cux(SiO2)1􀀀x nanocomposite lms around the percolation threshold xC in the temperature range of 4 30 K and frequencies of 20 MHz. The behavior of low-frequency ReZ(T) dependences displayed the predominance of electrons hopping between the closest Cu-based nanoparticles for the samples below the percolation threshold xC = 0:59 and nearly metallic behaviour beyond the xC. The high-frequency curves ReZ(f) at temperatures T > 10 K for the samples with x < xC exhibited behavior close to ReZ(f) f􀀀s with s 1:0 which is very similar to the known Mott law for electron hopping mechanism. For the samples beyond the percolation threshold (x > xC), the frequency dependences of ReZ(f) displayed inductive-like (not capacitive) behaviour with positive values of the phase shift angles.