Growth and characterization of radio-frequency plasma deposited gold-carbon composites

Abstract

Gold-hydrocarbon composite thin films with various metal volume fractions have been deposited by a combination of sputtering and plasma deposition in argon-propane plasma. Partial pressure control and optical spectroscopy of the gas phase have shown the growth processes to be partially dependent on the chemical reactions occurring on the substrate. The polymer matrix structure was analyzed by several techniques and found to consist of dense hydrocarbon with a density of 1.7. For low metal volume fractions, optical spectra of films show that the dielectric nature of the polymer predominates while the metallic phase governs the absorption phenomenon for gold-rich films. Electrical conductivity measurements have revealed the influence of graphitic structures in the film just above a metal volume fraction p=0.03, below which carbon-carbon sp2 bonds are more predominant. Similarly the percolation threshold has been found to occur at about p=0.3 and the conductivity exponent is evaluated at 1.55.