Optimizing crystal characterization of WO3–ZnO composites for boosting photoactive performance via manipulating crystal formation conditions

Abstract

In this study, the crystal quality, crystal features, and defect density of WO₃–ZnO composite nanorods were manipulated by modifying the growth temperature of ZnO thin films deposited through sputtering. Post-annealing procedures were conducted in a hydrogen-containing atmosphere to optimize the photoresponsivity of the composites. Radio-frequency sputtering was used to deposit a ZnO layer on the nanorod template at room temperature and at 400 °C. The composites were subjected to post-annealing procedures at 450 °C in a reducing gas atmosphere, after which they exhibited high photosensitivity. This can be attributed to the favorable oxygen vacancy concentration on the surface, as well as the small ZnO protrusions on the surface of the WO₃–ZnO composites. The substantial improvement in the photoinduced charge separation efficiency and interfacial transfer ability, which were achieved through the control of various process conditions, makes these composites suitable for applications in photoactive devices with high performance and stability.