Ultraviolet sensing mechanism and characteristics of environmentally friendly aligned aluminium doped zinc oxide nanorod arrays prepared using low cost solution growth method

Ultraviolet (UV) photoconductive sensors have been fabricated on glass substrates using aligned aluminium (Al) doped zinc oxide (ZnO) nanorod arrays at different annealing temperatures. The Al doped ZnO nanorod arrays were prepared using a novel technique of sonicated sol-gel immersion utilising Al doped ZnO nanoparticle thin film as seeded catalyst. In this study, the authors were able to increase the crystallinity of the Al doped ZnO nanorod arrays while maintaining the morphology of the Al doped ZnO nanorod after annealing process in ambient. The surface defects of the nanorod were significantly suppressed at high temperature up to 500 degrees C, as can be observed in the photoluminescence spectra. It has been demonstrated that the photoresponse of the UV sensor under 365 nm UV illumination showed significant improvement after the annealing process due to the high crystallisation degree of the ZnO nanostructures. The influences of surface defects on the photoresponse properties of the fabricated UV photoconductive sensor are discussed.