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Paper   IPM / P / 11572
School of Physics
  Title:   Morphology, Optical and Electrical Properties of Cu-Ni Nanoparticles in a-C:H Thin Films Prepared by Co-Deposition of RF-Sputtering and RF-PECVD
  Author(s): 
1.  T. Ghodselahi
2.  M.A. Vesaghia
3.  A. Gelalia
4.  H. Zahrabia
5.  S. Solaymania
  Status:   Published
  Journal: Appl. Surf. Sci.
  Vol.:  258
  Year:  2011
  Pages:   727-731
  Supported by:  IPM
  Abstract:
We study optical and electrical properties of Cu-Ni nanoparticles in hydrogenated amorphous carbon thin films (Cu-Ni NPs @ a-C:H) with different surface morphology. Thin films with 5, 10 and 15 nm thickness of Ni over layer were prepared by co-deposition of RF-sputtering and RF-Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) from acetylene gas and Cu and Ni target. By adding Ni over layer, a nonmetal-metal transition was observed. Surface morphology of the thin films was described by a Gaussian self-affine fractal, except the sample with 10 nm thickness of Ni over layer which is in the nonmetal- metal transition region. The self-affine fractal films show a two-dimensional fractal structures. X-ray diffraction profile indicates that Cu nanoparticles (Cu NPs) and Ni nanoparticles (Ni NPs) with fcc crystal structure are formed in these films. Localized Surface Plasmon Resonance peak (LSPR) of Cu NPs is observed around 600 nm in visible spectra which is widen and have a small blue shift due to the thickness of Ni over layer. The variation of conductivity of these bilayers is consistent with variation of width of LSPR peak. We assign both effects to electron delocalization of Cu NPs.

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