Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Metal and Semiconductor Substrates: Structure, Epitaxy and Growth
O 89.10: Talk
Thursday, March 20, 2025, 17:15–17:30, H8
Ab initio surface phase diagram of (AlxGayIn1−x−y)2O3 — •Qaem Hassanzada1, Yuanyuan Zhou1,2, and Matthias Scheffler1 — 1The Fritz Haber institute, Berlin, Germany — 2The Leibniz-Institut für Kristallzüchtung, Berlin, Germany
Group III sesquioxides with ultra-wide bandgaps are the most promising candidates for high-power electronics. Numerous efforts have been made to grow group-III sesquioxides, however, the fundamental understanding of growth process is still shallow. The prerequisite to understand growth process is detailed information about the surface geometry and stoichiometry under growth conditions. This can be provided in surface phase diagrams. In this study, we explore the surface phase diagram of Group III sesquioxides, (AlxGayIn1−x−y)2O3, for the entire compositional range, using ab initio atomistic thermodynamics [1, 2] and the sure-independence screening and sparsifying operator (SISSO) [3] machine learning methods. We predict the most probable phases under the corresponding growth conditions. For instance, in the Ga-rich region, we predict the formation of a Ga monolayer, which may be related to the experimental hypothesis of Ga adlayer formation at a lower O/Ga ratio [4] reminiscent of the phenomena in GaN.
[1] Scheffler, M. Studies in Surface Science and Catalysis, Vol. 40; Elsevier: 1988, pp 115−122. [2] Reuter, K.; Scheffler, M. Phys. Rev. B 2001, 65, 035406. [3] Ouyang, R. et al. M. Phys. Rev. Mater. 2018, 2, 083802. [4] Chou, T. et al. AIP Advances 2021, 11, 115323.
Keywords: Group III sesquioxides; surface phase diagram; ab initio atomistic thermodynamics; Machine learning