Split Ga vacancies: Abundant defects in β-Ga2O3

Filip Tuomisto*, Antti Karjalainen, Ilja Makkonen

*Corresponding author for this work

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


We have applied positron annihilation spectroscopy to study a wide range of β-Ga2O3bulk crystals and thin films with various doping levels. The Doppler broadening of the 511 keV positron-electron annihilation line exhibits colossal anisotropy compared to other three-dimensional crystalline semiconductors. State-of-the-art theoretical calculations of the positron characteristics in the β-Ga2O3lattice reveal that the positron state is effectively 1-dimensional, giving rise to strong anisotropy. Strongly relaxed split Ga vacancies are found to exhibit even stronger anisotropy and to dominate the positron annihilation signals in almost all experiments. The evidence leads to the conclusion that split Ga vacancies are abundant, with concentration of 1018 cm-3 or more, in β-Ga2O3samples irrespective of conductivity.

Original languageEnglish
Title of host publicationOxide-Based Materials and Devices XII
EditorsDavid J. Rogers, David C. Look, Ferechteh H. Teherani
ISBN (Electronic)9781510642096
Publication statusPublished - 2021
MoE publication typeA4 Article in a conference publication
EventOxide-Based Materials and Devices - Virtual, Online, United States
Duration: 6 Mar 202111 Mar 2021
Conference number: 12

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOxide-Based Materials and Devices
CountryUnited States
CityVirtual, Online


  • Compensation
  • Defect
  • Gallium oxide
  • positron annihilation spectroscopy
  • Vacancy


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