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Tailoring the electronic properties of monoclinic (InxAl1−x)2O3 alloys via substitutional donors and acceptors

Mohamed Abdelilah Fadla1,*, Myrta Grüning1,2, and Lorenzo Stella1

  • *Contact author: m.fadla@qub.ac.uk
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Phys. Rev. Materials 9, 105002 – Published 24 October, 2025

DOI: https://doi.org/10.1103/78f8-j9m2

Abstract

Ultrawide bandgap semiconductors such as β−Ga2O3 are ideal materials for next-generation power electronic devices. Electronic and mechanical properties of β−Ga2O3 can be tuned by alloying with other sesquioxides, notably Al2O3 and In2O3. Moreover, by tuning the In content of a (InxAl1−x)2O3 alloy, its lattice constants can be matched to those of Ga2O3, while preserving a large conduction-band offset. In view of potential applications to β−Ga2O3-based heterostructure, we performed atomistic modeling of (InxAl1−x)2O3 alloys using density functional theory to investigate thermodynamic and electrical properties of conventional group IV dopants (Si, Sn, C, Ge), alternative metal donors (Ta, Zr, Hf), and acceptors (Mg, Zn, Cu). The hybrid Heyd–Scuseria–Ernzerhof functional (HSE06) is used to accurately quantify the defect formation energies, ionization levels, and concentrations over a wide range of experimentally relevant conditions for the oxygen chemical potential and temperature. In our atomistic models, Hf and Zr show favorable properties as alternative donors to Si and other group IV impurities, especially under oxygen-poor conditions. Our findings also suggest that acceptors Mg, Zn, and Cu, while they cannot promote p doping, can be still beneficial for the compensation of unintentionally n-doped materials, e.g., to generate semi-insulating layers and improve rectification.

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Phys. Rev. Materials 9, 105002– Published 24 October, 2025
  • Received 9 July 2025
  • Revised 12 September 2025
  • Accepted 2 October 2025
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