MOCVD Epitaxy of α-(AlxGa1−x)2O3 (x =0–100%) on m-Plane Sapphire Substrate

Phase pure single crystal α-(Al
x
Ga
1−x
)
2
O
3
thin films are successfully grown on m-plane sapphire substrate via MOCVD. Comprehensive characterization by XRD, RSM mapping, atomic resolution STEM, Raman spectroscopy, SEM, AFM and XPS measurements reveal high quality epitaxial growth of α-(Al
x
Ga
1−x
)
2
O
3
thin films over the entire Al composition range (x=0–100%) and α-GaO/AlGaO superlattice structures with smooth surface morphology, sharp interfaces, and homogenous Al distribution. The bandgap energies of 5.41 eV (x=0) to 8.81 eV (x=1) are extracted from XPS measurements. The determined band offsets reveal a type-I band alignment at the α-AlGaO/GaOinterfaces with valance and conduction band offsets of 0.27 eV and 3.13 eV between α-Ga
2
O
3
and α-Al
2
O
3
, respectively.