Point defects in GaN and related group-III nitrides studied by means of positron annihilation

Akira Uedono, Shoji Ishibashi, Shigefusa F. Chichibu, Katsuhiro Akimoto

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Citations (Scopus)


Positron annihilation is a non-destructive technique for investigating vacancy-type defects in condensed matter. When a positron is implanted into a sample, it annihilates with an electron and emits two 511-keV γ quanta. From measurements of Doppler broadening spectra of the annihilation radiation and positron lifetimes, one can detect point defects such as monovacancies, vacancy clusters, and vacancy-impurity complexes. The regions sampled can range from the surface to a depth on the order of microns. In the present study, we have used the positron annihilation technique to study relationship between the impurity doping and vacancies in GaN. Defects in ion-implanted GaN and their annealing properties were studied. The defects introduced by the implantation were identified as divacancies, and the defect reaction during isochronal annealing were found to depend on ion spices. A relationship between intra-4f transitions of Er and vacancies was studied. A correlation between the defect concentration and the PL intensity was observed. We will demonstrate that the positron annihilation technique is sensitive to vacancy-type defects in GaN, and it can contribute to the development of optical and electronic devices based such materials.

Original languageEnglish
Title of host publicationGallium Nitride Materials and Devices VI
Publication statusPublished - 2011
EventGallium Nitride Materials and Devices VI - San Francisco, CA, United States
Duration: 2011 Jan 242011 Jan 27

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceGallium Nitride Materials and Devices VI
Country/TerritoryUnited States
CitySan Francisco, CA


  • GaN
  • ion implantation
  • point defect
  • Positron annihilation
  • rare-earth
  • vacancy


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