Investigations of some physical properties of ALD growth ZnO films: effect of crystal orientation on photocatalytic activity

ZnO films have great application potentials from optoelectronic devices to photocatalysis. Detailed film properties and relations between photocatalytic activities of annealed ZnO films grown on glass and corning glass substrates by Atomic Layer Deposition Technique (ALD) were reported in the current study. The structural evolutions were investigated by X-ray diffraction. Results showed that crystal orientations are strongly dependent on substrate materials. The optical band gap values of all films change between 3.26 and 3.24 eV with annealing. Lower electrical resistivity values were obtained for as-grown films. The morphological properties of the films were investigated by atomic force microscopy. In addition, the highest value of photoactivity was determined for ZnO films grown on corning glass substrate and annealed at 600 degrees C with a value of 53%. Relations between crystal orientations and photocatalytic activities showed that the crystal orientations, crystallite sizes, peak intensities, and dislocation density values are highly effective on photoactivities of ZnO films.