Effects of oxygen-gas flow rate on lattice dynamics and microstructure for Ga-doped ZnO thin films prepared by reactive plasma deposition

T. Yamamoto, T. Mitsunaga, M. Osada, K. Ikeda, S. Kishimoto, K. Awai, H. Makino, T. Yamada, T. Sakemi, S. Shirakata

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16 Citations (Scopus)

Abstract

The dependences of lattice constant, crystallite size and internal strain in the (100) direction for Ga-doped ZnO (GZO; Ga content, 3 wt%) films on O 2 gas flow rate (0-20 sccm) during deposition were investigated. GZO films have been prepared by reactive plasma deposition (RPD). A series of GZO thin films with a thickness of 200 nm were deposited on glass substrate at 200 °C. In the range of O2 gas flow rate from 0 to 10 sccm, from out-of-plane and in-plane X-ray diffraction (XRD) measurements, we find a large lattice constant of the c-axis and small changes in the lattice constant of the a-axis compared with those of undoped ZnO. This is in good agreement with the theoretical results for GZO crystals based on a model that the dominant defect is Ga at Zn sites (GaZn). Excess O2 gas flow increases both crystallite size and internal strain in the (100) direction and reduces the lattice constant of the c-axis for GZO films. This is caused by the formation of complex defects including n-type killers associated with vacant defects as determined by secondary-ion mass spectrometry (SIMS) and Raman spectroscopy.

Original languageEnglish
Pages (from-to)369-376
Number of pages8
JournalSuperlattices and Microstructures
Volume38
Issue number4-6
DOIs
Publication statusPublished - 2005 Oct
Externally publishedYes

Keywords

  • A first-principles electronic-band-structure calculation
  • Polycrystalline Ga-doped ZnO films
  • Raman spectroscopy
  • Reactive plasma deposition
  • Secondary-ion mass spectrometry
  • X-ray diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Yamamoto, T., Mitsunaga, T., Osada, M., Ikeda, K., Kishimoto, S., Awai, K., Makino, H., Yamada, T., Sakemi, T., & Shirakata, S. (2005). Effects of oxygen-gas flow rate on lattice dynamics and microstructure for Ga-doped ZnO thin films prepared by reactive plasma deposition. Superlattices and Microstructures, 38(4-6), 369-376. https://doi.org/10.1016/j.spmi.2005.08.007