Ultraviolet-enhanced room-temperature gas sensing by using floccule-like zinc oxide nanostructures

The self-aggregation of floccule-like ZnO nanostructures that were shaped by an anodic aluminum oxidation (AAO) template to improve photoactivation and sensing performance was demonstrated. Because of differences in the surface energy between the densely distributed nanopores of AAO templates, sputtered ZnO materials were located in constricted regions and aggregated into roughened nanostructures with a high surface-to-volume ratio. Because of the generation of oxygen ions by ultraviolet illumination, the room-temperature-sensing responses showed a high degree of linearity with a resistance variation of 1.758% per 100 ppm of octane gas. The optimized sensing performance of the self-organized ZnO nanostructures was increased and was 15.4 times higher than that of an unpatterned ZnO thin film.