Fourier transform infrared spectroscopic study of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition

Sausan Al-Riyami, Shinya Ohmagari, Tsuyoshi Yoshitake

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    Nitrogen-doped ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films, which possess n-type conduction with enhanced electrical conductivities, were prepared by pulsed laser deposition and they were structurally studied by Fourier transform infrared (FTIR) spectroscopy. The film with a nitrogen content of 7.9 at.% possessed n-type condition with an electrical conductivity of 18 S/cm at 300 K. The FTIR spectra revealed peaks due to nitrogen impurities, C = N, C-N, and CHn (n = 1, 2, 3) bands. The sp2-CHn/(sp2-CHn + sp 3-CHn), estimated from the area-integration of decomposed peaks, were 24.5 and 19.4% for undoped and 7.9 at.% doped films, respectively. The nitrogen-doping not only form the chemical bonds between carbon and nitrogen atoms such as C = N and C-N bonds but also facilitate the formation of both sp2 and sp3 bonds, in particular, the sp 3-CHn bond is preferentially formed. From the analysis of the FTIR spectra, it was found that the hydrogen content in the film is increased with an increase in the nitrogen content. The increased hydrogen content might be owing to the enhanced volume of grain boundaries (GBs) between UNCD grains, and those between UNCD grains and an a-C:H matrix, which is caused by a reduction in the UNCD grain size. The CHn peaks predominantly come from an a-C:H matrix and GBs. Since the nitrogen-doping for a-C:H has been known to be hardly effective, the n-type conduction with the enhanced electrical conductivities might be attributed to the sp2-CHn formation at the GBs.

    Original languageEnglish
    Pages (from-to)1072-1075
    Number of pages4
    JournalDiamond and Related Materials
    Volume20
    Issue number7
    DOIs
    Publication statusPublished - Jul 1 2011

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Chemistry(all)
    • Mechanical Engineering
    • Physics and Astronomy(all)
    • Materials Chemistry
    • Electrical and Electronic Engineering

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