Vacancy Defects in Ga2O3: First-Principles Calculations of Electronic Structure

Abay Usseinov; Zhanymgul Koishybayeva; Alexander Platonenko; Vladimir Pankratov; Yana Suchikova; Abdirash Akilbekov; Maxim Zdorovets; Juris Purans; Anatoli I Popov

doi:10.3390/ma14237384

Vacancy Defects in Ga₂O₃: First-Principles Calculations of Electronic Structure

Materials (Basel). 2021 Dec 2;14(23):7384. doi: 10.3390/ma14237384.

Authors

Affiliations

¹ Faculty of Physics and Technical Sciences, L.N. Gumilyov Eurasian National University, Nur-Sultan 010008, Kazakhstan.
² Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., LV-1063 Riga, Latvia.
³ Department of Physics and Methods of Teaching Physics, Berdyansk State Pedagogical University, 71100 Berdyansk, Ukraine.
⁴ Department of Intelligent Information Technologies, Ural Federal University, 620075 Yekaterinburg, Russia.

Abstract

First-principles density functional theory (DFT) is employed to study the electronic structure of oxygen and gallium vacancies in monoclinic bulk β-Ga₂O₃ crystals. Hybrid exchange-correlation functional B3LYP within the density functional theory and supercell approach were successfully used to simulate isolated point defects in β-Ga₂O₃. Based on the results of our calculations, we predict that an oxygen vacancy in β-Ga₂O₃ is a deep donor defect which cannot be an effective source of electrons and, thus, is not responsible for n-type conductivity in β-Ga₂O₃. On the other hand, all types of charge states of gallium vacancies are sufficiently deep acceptors with transition levels more than 1.5 eV above the valence band of the crystal. Due to high formation energy of above 10 eV, they cannot be considered as a source of p-type conductivity in β-Ga₂O₃.

Keywords: DFT; deep donor; oxygen vacancy; p-type conductivity; point defects; β-Ga2O3.