Thermal annealing effects on the dynamic photoresponse properties of Al-doped ZnO nanowires network

In this study, UV photodetectors based on a network of aluminium-doped zinc oxide (AZO) nanowires were manufactured at a low cost; for this purpose, a fast and simple fabrication process that involved dropping nanowires dispersion solution was employed instead of the conventional e-beam lithography process that is used to manufacture single nanowire–based UV photodetectors. It was demonstrated that nanowire network–based UV photodetectors provide a much faster UV photoresponse than conventional single nanowire–based UV photodetectors. The fast UV photoresponse of the fabricated UV photodetector can be attributed to the fact that the potential barriers formed in the nanowire network junctions effectively block the flow of electrons during the process of photocurrent decay. Furthermore, the UV photoresponse under illumination by a 254 nm UV source was studied as a function of the annealing temperature of the AZO nanowires network at a bias of 5 V. The fabricated UV photodetector showed the fastest response of 2 s to UV illumination in air when the sample was annealed in air for 1 h at 300 °C.

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► Nanowires network UV sensors show fast UV photoresponse property.
► UV sensors showed the fastest response of 2 s when the sample was annealed in air for 1 h at 300 °C.
► Potential barriers formed in nanowire junctions block the flow of electrons in photocurrent decay.