Optical properties of ultrananocrystalline diamond/amorphous carbon composite films prepared by pulsed laser deposition

Akira Nagano, Tsuyoshi Yoshitake, Takeshi Hara, Kunihito Nagayama

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    Ultrananocrystalline diamond (UNCD)/amorphous carbon (a-C) composite thin films were grown in ambient hydrogen by pulsed laser deposition using a graphite target, and their optical properties were determined by optical absorption spectroscopy and Raman scattering spectroscopy. Three optical bandgaps exist. Two bandgaps are indirect and their values were estimated to be 1.0 eV and 5.4 eV; these bandgaps correspond to the a-C surrounding the UNCDs and the UNCDs respectively. The third bandgap is direct and has a value of 2.2 eV, which significantly contributes to a large absorption coefficient, (106 cm- 1 at 3.0 eV). Possible origins of the third bandgaps are the grain boundaries (GBs) between the UNCDs and the a-C since they are specific to the UNCD/a-C composite films. The infrared absorption spectrum and the Raman scattering spectrum revealed the incorporation of hydrogen in the GBs. The hydrogen incorporated in the GBs might also have some influence on the appearance of the direct bandgap and its value.

    Original languageEnglish
    Pages (from-to)1199-1202
    Number of pages4
    JournalDiamond and Related Materials
    Volume17
    Issue number7-10
    DOIs
    Publication statusPublished - Jul 1 2008

    Fingerprint

    Diamond
    Carbon films
    Amorphous carbon
    Composite films
    Pulsed laser deposition
    pulsed laser deposition
    Diamonds
    Energy gap
    Optical properties
    diamonds
    optical properties
    composite materials
    carbon
    Hydrogen
    Grain boundaries
    grain boundaries
    Raman scattering
    hydrogen
    Graphite
    Raman spectra

    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

    Cite this

    Optical properties of ultrananocrystalline diamond/amorphous carbon composite films prepared by pulsed laser deposition. / Nagano, Akira; Yoshitake, Tsuyoshi; Hara, Takeshi; Nagayama, Kunihito.

    In: Diamond and Related Materials, Vol. 17, No. 7-10, 01.07.2008, p. 1199-1202.

    Research output: Contribution to journalArticle

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