Tackling Disorder in γ‐Ga 2 O 3
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- Department of Materials Imperial College London London SW7 2AZ UK, Center for Computational Chemistry School of Chemistry University of Bristol Bristol BS8 1TS UK
- Department of Electrical and Electronic Engineering Saga University Saga 840‐8502 Japan
- Technische Universität Berlin Institute of Solid State Physics Hardenbergstrasse 36 10623 Berlin Germany
- Institut für Physik Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 39106 Magdeburg Germany
- Paul‐Drude‐Institut für Festkörperelektronik Leibniz‐Institut im Forschungsverbund Berlin e.V. Hausvogteiplatz 5‐7 10117 Berlin Germany
- Leibniz‐Institut für Kristallzüchtung Max‐Born‐Str. 2 12489 Berlin Germany
- Department of Materials University of Oxford Parks Road Oxford OX1 3PH UK
- Stephenson Institute for Renewable Energy and Department of Physics University of Liverpool Liverpool L69 7ZF UK
- Diamond Light Source Ltd. Diamond House Harwell Science and Innovation Campus Didcot OX11 0DE UK
- Department of Chemistry University College London 20 Gordon Street London WC1H 0AJ UK
- Deutsches Elektronen‐Synchrotron DESY Notkestrasse 85 22607 Hamburg Germany
- Lawrence Livermore National Laboratory Livermore CA 94550 USA
Abstract Ga 2 O 3 and its polymorphs are attracting increasing attention. The rich structural space of polymorphic oxide systems such as Ga 2 O 3 offers potential for electronic structure engineering, which is of particular interest for a range of applications, such as power electronics. γ‐Ga 2 O 3 presents a particular challenge across synthesis, characterization, and theory due to its inherent disorder and resulting complex structure–electronic‐structure relationship. Here, density functional theory is used in combination with a machine‐learning approach to screen nearly one million potential structures, thereby developing a robust atomistic model of the γ‐phase. Theoretical results are compared with surface and bulk sensitive soft and hard X‐ray photoelectron spectroscopy, X‐ray absorption spectroscopy, spectroscopic ellipsometry, and photoluminescence excitation spectroscopy experiments representative of the occupied and unoccupied states of γ‐Ga 2 O 3 . The first onset of strong absorption at room temperature is found at 5.1 eV from spectroscopic ellipsometry, which agrees well with the excitation maximum at 5.17 eV obtained by photoluminescence excitation spectroscopy, where the latter shifts to 5.33 eV at 5 K. This work presents a leap forward in the treatment of complex, disordered oxides and is a crucial step toward exploring how their electronic structure can be understood in terms of local coordination and overall structure.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); Engineering and Physical Sciences Research Council (EPSRC); Thomas Young Center; German Research Foundation (DFG); Diamond Light Source; Deutsches Elektronen-Synchrotron (DESY); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Grant/Contract Number:
- AC52-07NA27344; EP/P033253/1; TYC-101; EP/P020194/1; EP/T022213/1; 446185170; EP/L01551X/1; SI21430-1; SI24670-1; H-20010087; 22-SI-003
- OSTI ID:
- 1882028
- Alternate ID(s):
- OSTI ID: 1882029; OSTI ID: 1883027
- Report Number(s):
- LLNL-JRNL-836215; 2204217
- Journal Information:
- Advanced Materials, Journal Name: Advanced Materials Vol. 34 Journal Issue: 37; ISSN 0935-9648
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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