Structural and optical properties of Ga2O3:In films deposited on MgO (1 0 0) substrates by MOCVD

Ga2O3:In films with different indium (In) content x [x=In/(Ga+In) atomic ratio] have been deposited on MgO (1 0 0) substrates by metalorganic chemical vapor deposition (MOCVD). Structural analyses revealed that the film deposited with actual In content (x′) of 0.09 was an epitaxial film and the films with x′=0.18 and 0.37 had mixed-phase structures of monoclinic Ga2O3 and bixbyite In2O3. The absolute average transmittance of the obtained films in the visible region exceeded 95%, and the band gap was in the range of 4.74–4.87 eV. Photoluminescence (PL) measurements were performed at room temperature, in which the visible luminescences were strong and could be seen by the naked eye. The strong emissions in the visible light region were proposed to originate from the gallium vacancies, oxygen deficiencies and other defects in these films.