Boosting performances of ZnO microwire homojunction ultraviolet self-powered photodetector by coupled interfacial engineering and plasmonic effects

A highly sensitive self-biased ultraviolet (UV) photodetector is largely desirable in practical applications. This work develops a one-dimensional ZnO homojunction photodiode, which includes an Sb-doped ZnO microwire with surface-covered by Ag nanowires (AgNWs@ZnO:Sb MW), a MgO buffer nanolayer, and a ZnO film. The photodiode is dramatically sensitive to UV light, with its photosensitive performances of a large on/off ratio of approximately 10⁷, a maximum responsivity of 292.2 mA W⁻¹, a high specific detectivity of 6.9 × 10¹³ Jones, and a rapid response speed in microseconds (16.4/465.1 µs) under 365-nm light illumination via 10 µW cm⁻² at 0 V bias. In particular, the highest external quantum efficiency approaching 99.3% is achieved. The modulation of the MgO nanofilm and surface-modified AgNWs on the improved photoresponse was carefully examined. Acting as a self-biased optical receiver, this photodiode was further integrated into a UV communication system that can transmit information in real time. Also, a 9 × 9 photodetector array based on the AgNWs@p-ZnO:Sb MW/i-MgO/n-ZnO homojunction exhibited a uniform distribution of light response and could be used as a workable photosensory to achieve good spatial resolution images. This work proposes a promising route for the design of high-performance UV photodetectors for realistic applications with low power consumption and large-scale construction.