Deep level defect states in β-, α-, and ϵ-Ga2O3crystals and films: Impact on device performance

Alexander Y. Polyakov, Vladimir I. Nikolaev, Eugene B. Yakimov, Fan Ren, Stephen J. Pearton, Jihyun Kim

Research output: Contribution to journalReview articlepeer-review

41 Citations (Scopus)


A review is given of reported trap states in the bandgaps of different polymorphs of the emerging ultrawide bandgap semiconductor Ga2O3. The commonly observed defect levels span the entire bandgap range in the three stable (β) or meta-stable polymorphs (α and ϵ) and are assigned either to impurities such as Fe or to native defects and their complexes. In the latter case, the defects can occur during crystal growth or by exposure to radiation. Such crystalline defects can adversely affect material properties critical to device operation of transistors and photodetectors, including gain, optical output, threshold voltage by reducing carrier mobility, and effective carrier concentration. The trapping effects lead to degraded device operating speed and are characterized by long recovery transients. There is still significant work to be done to correlate experimental results based on deep level transient spectroscopy and related optical spectroscopy techniques to density functional theory and the dominant impurities present in the various synthesis methods to understand the microscopic nature of defects in Ga2O3.

Original languageEnglish
Article number020804
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number2
Publication statusPublished - 2022 Mar 1

Bibliographical note

Funding Information:
The work in Russia was supported, in part, by the Russian Science Foundation, Grant No. 19-19-00409. The work at UF was performed as part of Interaction of Ionizing Radiation with Matter University Research Alliance (IIRM-URA), sponsored by the Department of the Defense, Defense Threat Reduction Agency under Award No. HDTRA1-20-2-0002 (Jacob Calkins). The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred. The work at UF was also supported by NSF DMR under No. 1856662 (James Edgar). The work of Jihyun Kim was financially supported by the Institute of Civil Military Technology Cooperation, funded by the Defense Acquisition Program Administration and Ministry of Trade (No. 20-CM-BR-05), and the National Research Foundation of Korea (No. 2020M3H4A3081799) Korea. The valuable help of P. B. Lagov (NUST MISiS) with irradiations; of N. B. Smirnov, I. V. Shchemerov, A. V. Chernykh, A. I. Kochkova, and A. A. Vasilev of NUST MISiS; and of S. Stepanov and A. Pechnikov at the Ioffe Institute is greatly appreciated.

Publisher Copyright:
© 2022 Author(s).

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


Dive into the research topics of 'Deep level defect states in β-, α-, and ϵ-Ga2O3crystals and films: Impact on device performance'. Together they form a unique fingerprint.

Cite this