Structure and properties of a-C films modified with Ir nanoparticles

Abstract

In this work, thin amorphous carbon films modified with iridium nanoparticles (a-C <Ir>) synthesized by magnetron ion-plasma co-sputtering in an argon atmosphere are considered.The morphology and structure of a-C <Ir> films were studied using atomic-force microscopy and Raman spectroscopy. The dispersion of the G peak showed structural changes of a-C with increasing Ir concentration in the films, which is more clearly manifested in the films synthesized on silicon substrates. The optical and electrical properties of a-C <Ir> films were studied. A change in the band gap with increasing Ir concentration additionally showed a structural transition from a diamond-like to a graphite-like matrix. A percolation transition of conductivity at Ir concentration of ∼0.2 at.% in a-C <Ir> films was detected and an increase in conductivity by 107 when the concentration of iridium was increased by 0.7 at.%.