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

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

doi:10.3390/ma14237384

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.

Highlights

Gallium oxide (β-Ga2O3), well known for its unique optical and electrical properties, as a semiconductor with a wide band gap (4.9–5.0 eV), has shown a constantly growing interest as a promising material in different fields of power electronics, optoelectronics, and photonics in recent years [1,2,3]
Many first-principle calculations devoted to the study of oxygen vacancies in β-Ga2O3 suggest that they are rather deep than shallow donors with charge transition levels below 1 eV from the bottom of the conduction band [11,12,13,14,15,16]
In our previous hybrid B3LYP study on oxygen vacancies in β-Ga2O3 [18], it was shown that vacancies create deep donor levels and no have contribution to observable n-type conductivity

Summary

Introduction

Gallium oxide (β-Ga2O3), well known for its unique optical and electrical properties, as a semiconductor with a wide band gap (4.9–5.0 eV), has shown a constantly growing interest as a promising material in different fields of power electronics, optoelectronics, and photonics in recent years [1,2,3]. Many first-principle calculations devoted to the study of oxygen vacancies in β-Ga2O3 suggest that they are rather deep than shallow donors with charge transition levels below 1 eV from the bottom of the conduction band [11,12,13,14,15,16].

Results

Conclusion