Preparation and characterization of amorphous hydrogenated carbon films containing Au nanoparticles from heat-treatment of polymer precursors

Amorphous hydrogenated carbon (aC:H) films containing Au nanoparticles have been successfully prepared by heat-treatment of the precursors including poly(phenylcarbyne) polymer and HAuCl₄ at 600 °C in Ar atmosphere. The microstructure and morphology of the obtained films were investigated by means of Raman, XPS, XRD, TEM, and AFM. The sheet resistivity of the films was measured by a four-point probe method. Moreover, a ball-on-disc test was employed to obtain information about the frictional properties and sliding wear resistance of the films. The results show that heat-treatment of the precursors at 600 °C causes the change of the polymer into amorphous hydrogenated carbon phase, and the reduction of AuCl₄^- anions into zero-valence Au. All of the AuaC:H films exhibit smooth morphologies, with the RMS roughness smaller than 0.80 nm. Au nanoparticles are well dispersed in the amorphous carbon matrix, with size ranging from several to tens of nanometers, and the particle size increases with increasing gold content. The incorporation of Au in the carbon matrix can drastically decrease the resistivity and the resistivity of composite films gradually decreases with increasing Au concentration. AuaC:H films with the Au concentration of 2% and 4% show much better friction-reduction and wear-resistance than aC:H film. PACS 81.15.Np; 81.07.-b; 81.40.Pq