Structural and optical properties of facet-controlled MOVPE grown c-GaN on <i>β</i>-Ga₂O₃ (100) substrates

Abstract This study reports the structural and optical characterisation of GaN layers grown on β -Ga 2 O 3 substrates using a three-step facet-controlled MOVPE growth process. Surface morphology was analyzed using AFM and SEM, while high-resolution XRD provided insights into structural quality and orientation. Orientational dependence in the planar direction was obtained from the diffraction pattern at the GaN/ β -Ga 2 O 3 interface. TEM and STEM imaging revealed dislocation densities and their reduction at the facet layer. Oxygen and nitrogen diffusion at the GaN/ β -Ga 2 O 3 interface was determined using EELS measurements, while optical properties were assessed using temperature-dependent photoluminescence and ellipsometry.