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Journal of Radioanalytical and Nuclear Chemistry

, Volume 211, Issue 1, pp 31–38 | Cite as

Positron/positronium annihilation in nanocrystalline silicon thin films

  • X. Zhao
  • Y. Itoh
  • Y. Aoyagi
  • T. Sugano
  • K. Hirata
  • Y. Kobayashi
  • T. Ohdaira
  • R. Suzuki
  • T. Mikado
Contributed Papers

Abstract

Positron and positronium annihilation investigations were applied to nanocrystalline silicon (nc-Si) thin films, for the first time. The nc-Si thin films with average grain diameters of 3–5 nm show intense blue luminescence at room temperature. The nanometer-sized Si crystallites formed in amorphous Si (a-Si) matrix give rise to this luminescence. Very highS-parameters up to 0.62 were observed in the as-grown a-Si thin film suggesting positronium formation in the a-Si layer. The average lifetime of the positrons in the a-Si was determined to be about 520 ps. TheS-parameters dropped significantly to 0.53 by crystallization of the thin film at 800 °C for 10 seconds, which was almost the same to the value observed in bulk Si (100) substrate. Further crystallization from 60 seconds to 1 hour showed smaller change in theS-parameters than that from the a-Si to 10 seconds. The large change in theS-parameters due to the annealing might be caused by the formation of Si nanocrystallites in a-Si matrix suggesting that positron is a sensitive probe for structural investigations of the nc-Si materials.

Keywords

Silicon Physical Chemistry Crystallization Thin Film Inorganic Chemistry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Akadémiai Kiadó 1996

Authors and Affiliations

  • X. Zhao
    • 1
  • Y. Itoh
    • 1
  • Y. Aoyagi
    • 1
  • T. Sugano
    • 1
  • K. Hirata
    • 2
  • Y. Kobayashi
    • 2
  • T. Ohdaira
    • 3
  • R. Suzuki
    • 3
  • T. Mikado
    • 3
  1. 1.The Institute of Physical and Chemical Research (RIKEN)Saitama(Japan)
  2. 2.National Institute of Materials and Chemical ResearchTsukuba, Ibaraki(Japan)
  3. 3.Electrotechnical LaboratoryTsukuba, Ibaraki(Japan)

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