Structural and optical properties of nano-structured tungsten-doped ZnO thin films grown by pulsed laser deposition

B. D. Ngom*, T. Mpahane, N. Manyala, O. Nemraoui, Ulrich Buttner, J. B. Kana, A. Y. Fasasi, M. Maaza, A. C. Beye

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    59 Scopus citations

    Abstract

    Novel highly c-oriented tungsten-doped zinc oxide (WZO) thin films with 1 wt% were grown by pulsed laser deposition (PLD) technique on corning 1737F glass substrate. The effects of laser energy on the structural, morphological as well as optical transmission properties of the films were studied. The films were highly transparent with average transmittance exceeding 87% in the wavelength region lying between 400 and 2500 nm. X-ray diffraction analysis (XRD) results indicated that the WZO films had c-axis preferred orientation with wurtzite structure. Film thickness and the full width at half maximum (FWHM) of the (0 0 2) peaks of the films were found to be dependent on laser fluence. The composition determined through Rutherford backscattering spectroscopy (RBS) appeared to be independent of the laser fluence. By assuming a direct band gap transition, the band gap values of 3.36, 3.34 and 3.31 eV were obtained for corresponding laser fluence of 1, 1.7 and 2.7 J cm -2 , respectively. Compared with the reported undoped ZnO band gap value of 3.37 eV, it is conjectured that the observed low band gap values obtained in this study may be attributable to tungsten incorporation in the films as well as the increase in laser fluence. The high transparency makes the films useful as optical windows while the high band gap values support the idea that the films could be good candidates for optoelectronic applications.

    Original languageEnglish (US)
    Pages (from-to)4153-4158
    Number of pages6
    JournalApplied Surface Science
    Volume255
    Issue number7
    DOIs
    StatePublished - Jan 15 2009

    Keywords

    • Laser ablation
    • Nano-structures
    • Optical windows
    • Semiconductor
    • Thin film

    ASJC Scopus subject areas

    • Chemistry(all)
    • Condensed Matter Physics
    • Physics and Astronomy(all)
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films

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