Annealing effect on the optical and electronic properties of β-Ga2O3/AZO multilayered films

Beta-gallium oxide/Aluminum-doped zinc oxide (β-Ga2O3/AZO) multilayered films consisting of three bilayers of 100-nm β-Ga2O3 and 400-nm AZO have been successfully prepared on sapphire substrates by magnetron sputtering. The microstructure of the β-Ga2O3/AZO film is investigated in detail using X-ray diffractometer, scanning electron microscope, Energy Dispersive Spectrometer, Hall measurement system and UV–Vis–NIR spectrophotometer. It is found that the optical and electronic properties of the films are manipulated by the annealing temperature. The films annealed at 800 °C exhibit the best properties with the out-of-plane orientation of ZnO (001)||Al2O3 (0001). The Hall mobility of this film is 14.47 cm2 V−1 s−1 and the average transmittance is about 94 %. The optical band gap is 3.25 eV. These results indicate that the β-Ga2O3/AZO multilayered films are appealing candidate for photoelectric device applications.