Tungsten-incorporation induced red-shift in the bandgap of gallium oxide thin films

Tungsten (W) incorporated Ga2O3 films were produced by co-sputter deposition. W-concentration was varied by the applied sputtering-power. The structure and optical properties of W-incorporated Ga2O3 films were evaluated using X-ray diffraction, scanning electron microscopy, and spectrophotometric measurements. No secondary phase formation was observed in W-incorporated Ga2O3 films. W-induced effects were significant on the structure and optical properties of Ga2O3 films. The bandgap of Ga2O3 films without W-incorporation was ∼5 eV. Red-shift in the bandgap was noted with increasing W-concentration indicating the electronic structure changes in W-Ga2O3 films. A functional relationship between W-concentration and optical property is discussed.