Enhanced recovery speed of nanostructured ZnO photodetectors using nanobelt networks

ZnO nanowire (NW) UV photodetectors (PDs) have high sensitivity, while their long recovery time is an important limitation for practical applications. We demonstrated that the recovery time of nanostructured ZnO PDs can be significantly improved using the nanobelt (NB) network. The NB-network PDs are fabricated by only one step without tedious and costly lithography processes. As compared with a recovery time of 32.95s in the single NB-based PD, a fast recovery time of 0.53s observed in the NB-network PDs is achieved due to the existence of the NB-NB junction barriers. As the junction barriers accounting for the poor conductivity of NB networks hinder the electron transport, the dark current of the NB-network PDs is two orders of magnitude lower than that of the single NB-based PDs. The NB networks can be applicable to the building structures for nanostructured ZnO-based light-sensing applications with wafer-scale uniformity without compromising the unique photodetection properties exclusively provided by high surface-to-volume ratio and reduced dimensionality of an individual NW/NB.