Persistent Room-Temperature Photodarkening in Cu-Doped β-Ga₂O₃

Authors

• J. Jesenovec, Washington State University
• C. Pansegrau, Washington State University
• M. D. McCluskey, Washington State University
• J. S. McCloy, Washington State University
• Timothy D. Gustafson, Air Force Institute of Technology
• Larry E. Halliburton, West Virginia University
• J. B. Varley, Lawrence Livermore National Laboratory

Document Type

Article

Publication Date

2-16-2022

Abstract

β-Ga₂O₃ is an ultrawide band gap semiconductor with emerging applications in power electronics. The introduction of acceptor dopants yields semi-insulating substrates necessary for thin-film devices. In the present work, exposure of Cu-doped 𝛽−Ga₂⁢O₃ to UV light >4  eV is shown to cause large, persistent photo-induced darkening at room temperature. Electron paramagnetic resonance spectroscopy indicates that light exposure converts Cu²⁺ to Cu³⁺, a rare oxidation state that is responsible for the optical absorption. The photodarkening is accompanied by the appearance of O─H vibrational modes in the infrared spectrum. Hybrid function calculations show that Cu acceptors can favorably complex with hydrogen donors incorporated as interstitial (H_𝑖) or substitutional (H_O) defects. When Cu_Ga−H_O complexes absorb light, hydrogen is released, contributing to the observed Cu³⁺ species and O─H modes.

Comments

© 2022 American Physical Society

Plain-text title: Persistent Room-Temperature Photodarkening in Cu-Doped β-Ga2O3

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DOI

10.1103/PhysRevLett.128.077402

Source Publication

Physical Review Letters (ISSN 0031-9007 | eISSN 1079-7114)

Recommended Citation

Jesenovec, J., Pansegrau, C., McCluskey, M. D., McCloy, J. S., Gustafson, T. D., Halliburton, L. E., & Varley, J. B. (2022). Persistent Room-Temperature Photodarkening in Cu-Doped β-Ga2O3. Physical Review Letters, 128(7), 077402. https://doi.org/10.1103/PhysRevLett.128.077402