Atomic scale observation of threading dislocations in α-Ga₂O₃

This study presents a statistically significant investigation of threading dislocations in α-Ga₂O₃ using high-resolution transmission electron microscopy. All the dislocations, observed end-on, exhibit a projected Burgers vector b_e = 1/3 ⟨1-100⟩, with data revealing that the dislocations fall into three categories: perfect mixed (b = 1/3 ⟨1-101⟩) dislocations and edge (b = ⟨1-100⟩ and b = 1/3 ⟨11-20⟩) dislocations which dissociate into combinations of b = 1/3 ⟨1-100⟩ partials. High-resolution analysis of the core region of the dislocations identifies that all the dislocations exhibit a similar 5-atom core, when looking at the cation sites. This is the first investigation of its kind in this material system, which will inform future work to, for example, understand the electronic properties of dislocations in α-Ga₂O₃ and other epitaxial corundum-structured materials.