Vacancies and electron trapping centers in acidic ammonothermal GaN probed by a monoenergetic positron beam

Akira Uedono, Yusuke Tsukada, Yutaka Mikawa, Tae Mochizuki, Hideo Fujisawa, Hirotaka Ikeda, Kaori Kurihara, Kenji Fujito, Shigeru Terada, Shoji Ishibashi, Shigefusa F. Chichibu

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8 Citations (Scopus)

Abstract

Defects in ammonothermal GaN have been studied using a monoenergetic positron beam. Through measurements of Doppler broadening spectra of the annihilation radiation, the major defect species was identified as a Ga vacancy coupled with impurities such as oxygen and/or hydrogen. Those defects were found to be stable even after annealing at 1000 °C. The shape parameter S for the Doppler broadening spectrum corresponding to positron annihilation at the surface was found to be decreased by illumination within energy ranges of 1.5-2.6 eV and 3.2-3.6 eV. This phenomenon is attributed to the suppression of recombinations between holes and electrons due to trapping centers, which can hold electrons for a long time, and a resultant accumulation of holes at the surface. Recovery of the S value required almost one day, but it was shortened by the annealing at 1000 °C.

Original languageEnglish
Pages (from-to)117-121
Number of pages5
JournalJournal of Crystal Growth
Volume448
DOIs
Publication statusPublished - 2016 Aug 15

Keywords

  • A1. Point defect
  • A2. Single crystal growth
  • B1. Nitrides
  • B2. Semiconducting III-V materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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    Uedono, A., Tsukada, Y., Mikawa, Y., Mochizuki, T., Fujisawa, H., Ikeda, H., Kurihara, K., Fujito, K., Terada, S., Ishibashi, S., & Chichibu, S. F. (2016). Vacancies and electron trapping centers in acidic ammonothermal GaN probed by a monoenergetic positron beam. Journal of Crystal Growth, 448, 117-121. https://doi.org/10.1016/j.jcrysgro.2016.05.015