Investigation of β-Ga2O3 films and β-Ga2O3/GaN heterostructures grown by metal organic chemical vapor deposition

In this work, (-2 0 1) β-Ga2O3 films are grown on GaN substrate by metal organic chemical vapor deposition (MOCVD). It is revealed that the β-Ga2O3 film grown on GaN possesses superior crystal quality, material homogeneity and surface morphology than the results of common heteroepitaxial β-Ga2O3 film based on sapphire substrate. Further, the relevance between the crystal quality of epitaxial β-Ga2O3 film and the β-Ga2O3/GaN interface behavior is investigated. Transmission electron microscopy result indicates that the interface atom refactoring phenomenon is beneficial to relieve the mismatch strain and improve the crystal quality of subsequent β-Ga2O3 film. Moreover, the energy band structure of β-Ga2O3/GaN heterostructure grown by MOCVD is investigated by X-ray photoelectron spectroscopy and a large conduction band offset of 0.89 eV is obtained. The results in this work not only convincingly demonstrate the advantages of β-Ga2O3 films grown on GaN substrate, but also show the great application potential of MOCVD β-Ga2O3/GaN heterostructures in microelectronic applications.