Structural, morphological, FTIR and photoluminescence properties of gallium oxide thin films

Thin films of β-Ga2O3 are prepared on sapphire substrates via electron beam evaporation and annealed at 1000 °C for 1 h. The effect of the annealing treatment upon the crystal structures, surface morphologies, and optical properties of β-Ga2O3 films are investigated by x-ray diffraction, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and photoluminescence and optical transmittance spectra. The easily prepared β-Ga2O3 films present a mixed structure of amorphous and crystalline phases. The annealed β-Ga2O3 films exhibit a clear absorption edge in the deep ultraviolet region. Ultraviolet and red emissions are also observed in the photoluminescence spectra of the annealed β-Ga2O3 films.