Band alignment of orthorhombic Ga2O3 with GaN and AlN semiconductors

• High-quality orthorhombic Ga 2 O 3 epitaxial film grown on GaN, AlN and Sapphire substrate by pulsed laser deposition. • A unique type-I band alignment of κ -Ga 2 O 3 with GaN and AlN is observed. • There is a high conduction band offset of 1.38 eV and 1.04 eV for κ-Ga 2 O 3 /GaN, and κ -Ga 2 O 3 /AlN heterostructure. Ga 2 O 3 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 Ga 2 O 3 on sapphire, GaN, and AlN templates by the pulsed laser deposition technique. The initial characterizations show a two-dimensional mode of single-crystalline orthorhombic Ga 2 O 3 (κ-Ga 2 O 3 ) growth on these substrates with smooth surface morphology. Integrating κ-Ga 2 O 3 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-Ga 2 O 3 /GaN and κ-Ga 2 O 3 /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.