Optical and structural properties of Cu-doped β-Ga2O3 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-Ga2O3 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.

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► We prepare polycrystalline Cu-doped β-Ga2O3 films.
► Cu dopants cause poor crystal quality and shrinkage of the optical band gap.
► Cu-doping enhances the UV and blue emission.
► A new blue emission peak centre at 475 nm appears by Cu-doping.
► Cu dopants decrease the optical transmittance.