Band alignment of orthorhombic Ga₂O₃ with GaN and AlN semiconductors

Ga₂O₃ semiconductors have attracted tremendous research interests because of their fascinating material properties for future-generation energy, electronic, and optoelectronic applications. In the present study, we have performed the epitaxial growth of tin-doped Ga₂O₃ on sapphire, GaN, and AlN templates by the pulsed laser deposition technique. The initial characterizations show a two-dimensional mode of single-crystalline orthorhombic Ga₂O₃ (κ-Ga₂O₃) growth on these substrates with smooth surface morphology. Integrating κ-Ga₂O₃ with nitride semiconductors is interesting since both these materials possess polarization, which could induce 2-dimensional carrier gas (2DCG) at the interface. X-ray photoelectron spectroscopy studies reveal that both κ-Ga₂O₃/GaN and κ-Ga₂O₃/AlN heterostructure form a type-I band structure where the conduction band offset (CBO) was calculated to be 1.38 eV and 1.04 eV, respectively. This unique band alignment with high CBO could lead to the development of efficient power devices.