Growth of Ga2O3Regular Column Structures by Halide Vapour Phase Epitaxy: $\alpha$- and $\varepsilon$-phase Relation

Gallium oxide columnar structures have been grown by halide vapour phase epitaxy (HVPE) on patterned (0001) sapphire substrates. The grown samples have been investigated by XRD, optical transmission spectroscopy and SEM. The formation of α-Ga ₂ O ₃ columns on top of sapphire bumps and ε-Ga ₂ O ₃ in the valleys between bumps was observed.