Thermal evolution of defects in as-grown and electron-irradiated ZnO studied by positron annihilation

Chen, Z. Q., Wang, S. J., Maekawa, M., Kawasuso, A., Naramoto, H., Yuan, X. L. and Sekiguchi, T. (2007) Thermal evolution of defects in as-grown and electron-irradiated ZnO studied by positron annihilation. Physical Review B: Condensed Matter and Materials Physics, 75 24: 245206-1-245206-9. doi:10.1103/PhysRevB.75.245206

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Author Chen, Z. Q.
Wang, S. J.
Maekawa, M.
Kawasuso, A.
Naramoto, H.
Yuan, X. L.
Sekiguchi, T.
Title Thermal evolution of defects in as-grown and electron-irradiated ZnO studied by positron annihilation
Journal name Physical Review B: Condensed Matter and Materials Physics   Check publisher's open access policy
ISSN 1098-0121
Publication date 2007-06-13
Year available 2007
Sub-type Article (original research)
DOI 10.1103/PhysRevB.75.245206
Open Access Status File (Publisher version)
Volume 75
Issue 24
Start page 245206-1
End page 245206-9
Total pages 9
Place of publication New York, United States
Publisher American Physical Society Country
Language eng
Subject 0403 Geology
040306 Mineralogy and Crystallography
Abstract Vacancy-type defects in as-grown ZnO single crystals have been identified using positron annihilation spectroscopy. The grown-in defects are supposed to be zinc vacancy (VZn)-related defects, and can be easily removed by annealing above 600 °C. VZn-related defects are also introduced in ZnO when subjected to 3 MeV electron irradiation with a dose of 5.5×1018 cm−2. Most of these irradiation-induced VZn are annealed at temperatures below 200 °C through recombination with the close interstitials. However, after annealing at around 400 °C, secondary defects are generated. A detailed analysis of the Doppler broadening measurements indicates that the irradiation introduced defects and the annealing induced secondary defects belong to different species. It is also found that positron trapping by these two defects has different temperature dependences. The probable candidates for the secondary defects are tentatively discussed in combination with Raman scattering studies. After annealing at 700 °C, all the vacancy defects are annealed out. Cathodoluminescence measurements show that VZn is not related to the visible emission at 2.3 eV in ZnO, but would rather act as nonradiative recombination centers.
Keyword Thermal
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Julius Kruttschnitt Mineral Research Centre Publications
Excellence in Research Australia (ERA) - Collection
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Created: Fri, 15 Jan 2010, 14:24:01 EST by Macushla Boyle on behalf of Sustainable Minerals Institute