Optical and structural properties of Cu-doped β-Ga₂O ₃ films

The intrinsic and Cu-doped β-Ga₂O₃ films were grown on Si and quartz substrates by RF magnetron sputtering in an argon and oxygen mixture ambient. The effects of the Cu doping and the post thermal annealing on the optical and structural properties of the β-Ga ₂O₃ films were studied. The surface morphology, microstructure, optical transmittance, optical absorption, optical energy gap and photoluminescence of the β-Ga₂O₃ films were significantly changed after Cu-doping. After post thermal annealing, Polycrystalline β-Ga₂O₃ films were obtained, the transmittance decreased. After Cu-doping, the grain size decreased, the crystal quality deteriorated and the optical band gap shrunk. The UV, blue and green emission bands were observed and discussed. The UV and blue emission were enhanced and a new blue emission peak centred at 475 nm appeared by Cu-doping.