Structure and electrical properties of a-C∶H films deposited from CH4 decomposition in a low frequency discharge

a-C∶H films have been deposited from methane in a 20 KHz discharge. The Current Voltage characteristics of the plasma have been plotted as a function of the CH₄ pressure. It was shown that below 0.1 mbar the graphitic content in the films estimated from Raman Spectroscopy and Electron Energy Loss Spectroscopy is high enough to give electrical conductivity controlled by a percolation mechanism. It was also found that the a:c electrical responses of the deposited films are more sensitive to the structure than any other chemical analysis. The electrical analysis might be a good tool for structural investigations on a-C∶H films.