Effective Band Structure and Crack Formation Analysis in Pseudomorphic Epitaxial Growth of (InxGa1- x)2O3 Alloys: A First-Principles Study

Mohamed Abdelilah Fadla; Myrta Grüning; Lorenzo Stella

doi:10.1021/acsomega.3c10047

Effective Band Structure and Crack Formation Analysis in Pseudomorphic Epitaxial Growth of (In_xGa_{1- x})₂O₃ Alloys: A First-Principles Study

ACS Omega. 2024 Mar 20;9(13):15320-15327. doi: 10.1021/acsomega.3c10047. eCollection 2024 Apr 2.

Authors

Mohamed Abdelilah Fadla¹, Myrta Grüning^{1

2}, Lorenzo Stella^{1

3}

Affiliations

¹ School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, U.K.
² European Theoretical Spectroscopy Facility (ETSF).
³ School of Chemistry and Chemical Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AG, U.K.

Abstract

Ga₂O₃ is a promising material for power electronic applications. Alloying with In₂O₃ is used for band gap adjustment and reduction of the lattice mismatch. In this study, we calculate the effective band structure of 160-atom (In_xGa_1-x)₂O₃ supercells generated using special quasi-random structures where indium atoms preferentially substitute octahedral gallium sites in β-Ga₂O₃. We find that the disorder has a minimal effect on the lower conduction bands and does not introduce defect states. Employing the Heyd, Scuseria, and Ernzerhof (HSE06) hybrid functional, we accurately model the band gap, which remains indirect for all considered indium fractions, x, linearly decreasing from 4.8 to 4.24 eV in the range of x ∈ [0, 0.31]. Accordingly, the electron effective mass also decreases slightly and linearly. We determined the critical thickness for epitaxial growth of the alloys over β-Ga₂O3 surfaces along the [100], [010], and [001] directions. Our findings offer new insights into site preference, effective band structure, and crack formation within alloys.