  h-BN and Ga2O3 are two promising semiconductor materials. However, the band
alignment of the Ga2O3/h-BN heterojunction has not been identified, hindering
device development. In this study, the heterojunction was prepared by
metalorganic chemical vapor deposition and pulsed laser deposition.
Transmission electron microscopy confirmed sharp heterointerface and revealed
structural evolution as amorphous-Ga2O3 grew thicker on lattice mismatched
h-BN. The valence and conduction band offsets were determined by
high-resolution X-ray photoemission spectroscopy to be 1.75 and 3.35-3.65 eV,
respectively, corresponding to a type-II heterojunction. The extremely large
type-II band offsets along with indirect bandgap of Ga2O3 may be leveraged for
exceptional electron confinement and storage.
