Structural and optical properties of heteroepitaxial beta Ga2O3 films grown on MgO (100) substrates

Abstract Gallium oxide (Ga 2 O 3 ) films were deposited on MgO (100) substrates by metalorganic vapor phase epitaxy. Structure analyses showed that the films deposited at 550–700 °C were epitaxial β-Ga 2 O 3 films with an out of plane relationship of β-Ga 2 O 3 (100)||MgO(100). The film deposited at 650 °C showed the best crystallinity and the microstructure of the film was investigated by high resolution transmission electron microscopy. A theoretical model of the growth mechanism was proposed and the in-plane epitaxial relationship was given to be β-Ga 2 O 3 [001]||MgO . A four-domain structure inside the epitaxial film was clarified. The β-Ga 2 O 3 film deposited at 650 °C showed an absolute average transmittance of 95.9% in the ultraviolet and visible range, which had an optical band gap of 4.87 eV.