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Title: Gallium Oxide Nanostructures for High Temperature Sensors

Gallium oxide (Ga 2O 3) thin films were produced by sputter deposition by varying the substrate temperature (T s) in a wide range (T s=25-800 °C). The structural characteristics and electronic properties of Ga 2O 3 films were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Rutherford backscattering spectrometry (RBS) and spectrophotometric measurements. The effect of growth temperature is significant on the chemistry, crystal structure and morphology of Ga 2O 3 films. XRD and SEM analyses indicate that the Ga 2O 3 films grown at lower temperatures were amorphous while those grown at T s≥500 oC were nanocrystalline. RBS measurements indicate the well-maintained stoichiometry of Ga 2O 3 films at T s=300-800 °C. The electronic structure determination indicated that the nanocrystalline Ga 2O 3films exhibit a band gap of ~5 eV. Tungsten (W) incorporated Ga 2O 3 films were produced by co-sputter deposition. W-concentration was varied by the applied sputtering-power. No secondary phase formation was observed in W-incorporated Ga 2O 3 films. W-induced effects were significant on the structure and electronic properties of Ga2O3 films. The band gap of Ga 2O 3 films without W-incorporation was ~5 eV. Oxygen sensor characteristics evaluated using optical andmore » electrical methods indicate a faster response in W-doped Ga 2O 3 films compared to intrinsic Ga 2O 3 films. The results demonstrate the applicability of both intrinsic and W-doped Ga-oxide films for oxygen sensor application at temperatures ≥700 °C.« less
  1. Univ. of Texas, El Paso, TX (United States)
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Technical Report
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Univ. of Texas, El Paso, TX (United States)
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United States