Ratcliff, Laura E, Oshima, Takayoshi, Nippert, Felix, Janzen, Benjamin M, Kluth, Elias, Goldhahn, Rudiger, Feneberg, Martin, Mazzolini, Piero, Bierwagen, Oliver, Wouters, Charlotte et al (show 12 more authors)
(2022)
Tackling Disorder in γ-Ga<sub>2</sub>O<sub>3</sub>.
ADVANCED MATERIALS, 34 (37).
e2204217-.
Abstract
Ga<sub>2</sub> O<sub>3</sub> and its polymorphs are attracting increasing attention. The rich structural space of polymorphic oxide systems such as Ga<sub>2</sub> O<sub>3</sub> offers potential for electronic structure engineering, which is of particular interest for a range of applications, such as power electronics. γ-Ga<sub>2</sub> O<sub>3</sub> 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<sub>2</sub> O<sub>3</sub> . 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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | electronic structure, gallium oxide, machine learning, photoluminescence excitation spectroscopy, semiconductors, structural disorder, ultrawide bandgap |
| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 18 Aug 2022 08:33 |
| Last Modified: | 05 Oct 2023 08:50 |
| DOI: | 10.1002/adma.202204217 |
| Open Access URL: | https://doi.org/10.1002/adma.202204217 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3161516 |
Dimensions
Dimensions
