Applied Surface Science, Vol.317, 1041-1046, 2014
Plasmonic properties of silver nanoparticles embedded in diamond like carbon films: Influence of structure and composition
In the present study optical properties of hydrogenated diamond like carbon nanocomposite films containing silver nanoparticles (DLC:Ag) deposited by direct current (DC) unbalanced reactive magnetron sputtering were studied in 180-1100 nm range. Different substrate bias was used during deposition of the films. Structure of the films was investigated by multiwavelength Raman scattering spectroscopy and X-ray diffractometry (XRD). Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS), surface morphology was investigated by atomic force microscopy (AFM). Red shift of the surface plasmon resonance peak of DLC:Ag films with the increase of Ag atomic concentration was observed. It was found that high atomic concentration of oxygen in DLC:Ag films results in some redshift of the plasmonic peak, too. Such a behavior is explained by increase of the refractive index of the dielectric medium surrounding silver nanoparticle due to possible presence of the silver oxide interlayer at the Ag nanocluster and diamond like carbon matrix interface. It was demonstrated that influence of the increased Ag atomic concentration on position of the surface plasmon resonance peak of DLC:Ag films clearly prevails influence of the increased sp(3)/sp(2) ratio of the diamond like carbon matrix. Correlation between the structure of Ag nanocrystallites studied by XRD and position of the surface plasmon resonance peak position was observed. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Diamond like carbon films containing silver;Reactive magnetron sputtering;Optical properties;Surface plasmon resonance;Raman scattering spectroscopy;Chemical composition