Structure and Photocatalysis of TiO₂/ZnO Double-Layer Film Prepared by Pulsed Laser Deposition

Abstract

Nanocrystalline double-layer film of TiO₂/ZnO was prepared by pulsed laser deposition on quartz substrate and their microstructure, optical property and photocatalysis were investigated. The first/bottom ZnO layer grew on its [001] direction of the wurtzite structure, while the second/top TiO₂ layer consisted of nanorods grown on the [001] direction of its anatase structure. The TiO₂/ZnO film showed improved photo-absorption in visible light in the UV–visible absorption spectrum; and showed weaken UV emission and enhanced deep level emission in the photoluminescence spectrum. By the degradation of methyl orange and methylene blue, the TiO₂/ZnO film exhibited evident enhanced photo-degradation efficiency in a wide wavelength range. That can be explained by the enhanced wavelength response in visible range, more effective use of irradiation light and the retarded recombination of electron–hole pairs in the double layer films.