Charge-Transfer Effect of GZO Film on Photochemical Water Splitting of Transparent ZnO@GZO Films by RF Magnetron Sputtering

With the purpose of enhancing the photochemical water splitting performance, GZO film has been used to increase the charge transfer of the ZnO@GZO films. The characterization of ZnO film, GZO film and ZnO@GZO films was carried out by X-ray diffraction (XRD), atomic force microscope, DRUV-vis spectra (DRUV-vis), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and photochemical water splitting. All samples show a related highly c-axis peak (002) from XRD patterns. DRUV-vis results show that the formed GZO film with wide band gap but low resistivity, would not affect the band gap of the ZnO@GZO films. PL results reveal that the decreased recombination of electron and hole, via the increased charge transfer by GZO film. XPS results hint that the obvious change of chemisorbed oxygen species on the surface of ZnO and GZO, and Ga atoms mainly substitute into Zn sites in the ZnO matrix. Compared with that of ZnO film, the ZnO@GZO films even with lower specific surface area, could efficiently enhance the photochemical water splitting performance via the charge-transfer effect of the GZO film.