Abstract
The presented work is about percolation mechanism of electrical conductivity of composite a-C:H films. The a-C:H thin films were deposited onto quartz substrates by ion-plasma magnetron sputteringmethod. High purity argon (Ar) and methane (CH4) gases mixture and combined target of polycrystallinegraphite with the purity of 99.99%, silver (99.99%) and titanium (99.99%) were used to produce а-С:Н films. Resistance of the produced films has been measured using «two probe» method to obtainconcentration dependence of electrical conductivity. Conductivity of a-C:H films was describedtheoretically in two ways: using the classical theory of percolation and a general effective medium (GEM)theory. Staircase percolation can be seen from the experimental results. The first percolation threshold occurs atthe concentration xc = 0.015 and the second one - at xc = 0.07. This could take place due to the fact that a-C:H composite material consist of two different inclusions, silver and titanium dioxide nanoparticles.The percolation mechanism of a-C:H film conductivity could be described by classical percolationtheory and by effective medium model as well.