Defect photoluminescence and structure properties of undoping (InxGa1-x)2O3 films and their dependence on sputtering pressure.

The (In x Ga 1-x) 2 O 3 thin films were deposited on sapphire substrates by radio frequency magnetron sputtering with increasing sputtering pressure from 0.6 Pa to 1.6 Pa. X-ray diffraction analysis indicated In composition of (In x Ga 1-x) 2 O 3 thin films maintained constant with the increase of sputtering pressure and In content and bandgaps of (In x Ga 1-x) 2 O 3 thin films were estimated to be 6% and 4.78 eV by Vegard's law, respectively. The influence of sputtering pressure on structural and optical properties was discussed in detail. Especially, the origin of different emission of (In x Ga 1-x) 2 O 3 thin films was investigated. The role of V Ga defects on the green emission centered at about 550 nm had been clarified. The energy band diagram of (In x Ga 1-x) 2 O 3 thin film was also proposed with intrinsic defect levels. • In content of (In x Ga 1-x) 2 O 3 films is 6% for all sputtering pressure condition. • Defects play an important role in luminescence. • Green luminescence is related to gallium vacancies. [ABSTRACT FROM AUTHOR]