Gallium oxide (Ga₂O₃) is an emerging ultra-wide bandgap semiconductor showing promising applications for ultraviolet photodetectors and high-power transistors [1]. The material can exist under different phases, namely α, β, κ, δ, γ, with the monoclinic β-phase being the thermodynamically stable variant. However the metastable phases, in particular the rhombohedral α-phase, is receiving increasing interest owing to its wider bandgap (ca. 5.3 eV) and prospects for alloying with  isomorphic sesquioxides [2]. However to unlock the exceptional potential of this material, a better understanding of its properties is necessary. We must in particular improve our understanding of defects, their properties and their impact on devices. 

This presentation will review recent investigations of the properties of defects (point defects and dislocations) in α-Ga₂O₃ using photoluminescence [3], photoconduction [4], cathodoluminescence, and transmission electron microscopy techniques.

[1] Pearton et al, Appl. Phys. Rev. 5, 011301 (2018) 

[2] Oshima et al, Appl. Phys. Lett. 121, 260501 (2022)

[3] Nicol et al, Appl. Phys. Lett. 122, 062102 (2023)

[4] Nicol et al, Phys. Status Solidi B 2300470 (2024; doi: 10.1002/pssb.202300470)