Persistent Room-Temperature Photodarkening in Cu-Doped β - Ga 2 O 3
- Washington State Univ., Pullman, WA (United States)
- Wright-Patterson Air Force Base, Dayton, OH (United States)
- West Virginia Univ., Morgantown, WV (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Beta-Ga2O3 is an ultra-wide bandgap 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 beta-Ga2O3 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 (Hi) or substitutional (HO) defects. When CuGa-HO complexes absorb light, hydrogen is released, contributing to the observed Cu3+ species and O-H modes.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Washington State Univ., Pullman, WA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; US Air Force Office of Scientific Research (AFOSR); LLNL Laboratory Directed Research and Development
- Grant/Contract Number:
- AC52-07NA27344; FG02-07ER46386; 22-SI-003; FA9550-18-1-0507
- OSTI ID:
- 1867090
- Alternate ID(s):
- OSTI ID: 1958027
- Report Number(s):
- LLNL-JRNL-834156; 1052559; TRN: US2306568
- Journal Information:
- Physical Review Letters, Vol. 128, Issue 7; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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