# Vacancy-type defects introduced by mechanical polishing in ammonothermal GaN studied by a monoenergetic positron beam

https://mdr.nims.go.jp/datasets/2d7d02af-1772-43d5-90b0-1580eb96ba9f

## File

- [Final manuscript.pdf](https://mdr.nims.go.jp/filesets/14333f20-2c5b-48df-a621-e6847bfd3473/download) ([Detail](https://mdr.nims.go.jp/filesets/14333f20-2c5b-48df-a621-e6847bfd3473.md))

## Id

2d7d02af-1772-43d5-90b0-1580eb96ba9f

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2026-04-17T11:38:04.527199Z

## Updated at

2026-04-19T23:56:29.772709Z

## Published at

2026-04-20T01:25:48.207401Z

## Doi

https://doi.org/10.48505/nims.6258

## First published url

https://doi.org/10.1016/j.jcrysgro.2026.128622

## Date published

2026-04-12

## Recorded date published

2026-8

## Resource type

journal_article

## Manuscript type

accepted_manuscript

## Collection



## Title

- title: Vacancy-type defects introduced by mechanical polishing in ammonothermal
    GaN studied by a monoenergetic positron beam
  title_type: original
  lang: en

## Description

- description: Vacancy-type defects introduced by mechanical polishing in basic ammonothermal
    GaN and their annealing behavior were studied using a monoenergetic positron beam.
    The major vacancy-type defect in the sample was identified as a Ga-vacancy (V<sub>Ga</sub>)
    coupled with hydrogen atoms. After mechanical polishing, high-density dislocations
    and stacking faults were introduced in the subsurface region (< 240 nm). In this
    region, the vacancy-type defects detected by positron annihilation were divacancies
    (V<sub>Ga</sub>V<sub>N</sub>) and their complexes with hydrogen atoms. After ultra-high-pressure
    annealing at 1400ºC, {0001} basal slip bands were the predominant defects observed
    using a transmission electron microscope. The major vacancy-type defects for the
    annealed samples were identified as V<sub>Ga</sub> coupled with multiple V<sub>N</sub>
    [ex V<sub>Ga</sub>(V<sub>N</sub>)<sub>3</sub>] and their complexes with hydrogen
    atoms. The observed annealing behavior of vacancies agreed with that estimated
    using photoluminescence spectroscopy.
  description_type: abstract
  lang: und

## Creator

- name: Akira Uedono
  role: author
  orcid: https://orcid.org/0000-0001-6224-4869
- name: Shoji Ishibashi
  role: author
  orcid: https://orcid.org/0000-0002-4896-3530
- name: Kohei Shima
  role: author
  orcid: https://orcid.org/0000-0003-0967-141X
- name: Shigefusa F. Chichibu
  role: author
- name: Kacper Sierakowski
  role: author
  orcid: https://orcid.org/0000-0002-9447-1182
- name: Makoto Oishi
  role: author
  orcid: https://orcid.org/0000-0003-3402-4556
- name: Noriyuki Okada
  role: author
  orcid: https://orcid.org/0009-0002-0090-5646
- name: Takuro Nagai
  role: author
  orcid: https://orcid.org/0000-0001-5239-3334
- name: Michal Bockowski
  role: author
  orcid: https://orcid.org/0000-0003-1616-685X

## Contact agent



## Publisher

organization: Elsevier BV

## Managing organization



## Keyword

- subject: Mechanical polishing
  schema: not_defined
- subject: GaN
  schema: not_defined
- subject: Vacancy
  schema: not_defined
- subject: Defect
  schema: not_defined
- subject: Positron annihilation
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by-nc/4.0/

## Other identifier(s)



## Data origin



## Embargo



## Journal

- title: Journal of Crystal Growth
  issn: '00220248'
  volume: '688'
  article_number: '128622'

## Conference



## Related item



## Funding

- identifier: JPMXP1223NM0137
  funder_name: Government of Japan Ministry of Education Culture Sports Science and
    Technology
- identifier: '101183211'
  funder_name: Horizon Europe

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## Measurement method



## Specimen



## Chemical composition



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## Fileset

- id: 14333f20-2c5b-48df-a621-e6847bfd3473
  filename: Final manuscript.pdf
  content_type: application/pdf
  size: 1017546
  md5: 41c63826ee21fe3357a69fa5f9336032

## Thumbnail

fileset_id: 14333f20-2c5b-48df-a621-e6847bfd3473
filename: Final manuscript.pdf