Transport and trap states in proton irradiated ultra-thick κ-Ga2O3

A. Y. Polyakov, V. I. Nikolaev, A. I. Pechnikov, E. B. Yakimov, P. B. Lagov, I. V. Shchemerov, A. A. Vasilev, A. I. Kochkova, A. V. Chernykh, In Hwan Lee, S. J. Pearton

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3 Citations (Scopus)


Changes induced by irradiation with 1.1 MeV protons in the transport properties and deep trap spectra of thick (>80 μm) undoped κ-Ga2O3 layers grown on sapphire are reported. Prior to irradiation, the films had a donor concentration of ∼1015 cm−3, with the two dominant donors having ionization energies of 0.25 and 0.15 eV, respectively. The main electron traps were located at Ec−0.7 eV. Deep acceptor spectra measured by capacitance-voltage profiling under illumination showed optical ionization thresholds near 2, 2.8, and 3.4 eV. The diffusion length of nonequilibrium charge carriers for ɛ-Ga2O3 was 70 ± 5 nm prior to irradiation. After irradiation with 1.1 MeV protons to a fluence of 1014 cm−2, there was total depletion of mobile charge carriers in the top 4.5 μm of the film, close to the estimated proton range. The carrier removal rate was 10-20 cm−1, a factor of 5-10 lower than in β-Ga2O3, while the concentration of deep acceptors in the lower half of the bandgap and the diffusion length showed no significant change.

Original languageEnglish
Article number032705
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number3
Publication statusPublished - 2023 May

Bibliographical note

Funding Information:
The work at National University of Science and Technology (NUST) MISiS was supported in part by a grant from the Ministry of Science and Higher Education of Russian Federation (Agreement No. 075-15-2022-1113). The work at UF was funded by the Defense Threat Reduction Agency (DTRA) as part of the Interaction of Ionizing Radiation with Matter University Research Alliance (IIRM-URA) under Contract No. HDTRA1-20-2-0002. 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 University of Florida (UF) was also supported by National Science Foundation (NSF) under No. DMR 1856662.

Publisher Copyright:
© 2023 Author(s).

ASJC Scopus subject areas

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


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