A transparent ultraviolet (UV) sensor using nanoheterojunctions (NHJs) composed of p-type NiO nanoflowers (NFs) and n-type ZnO nanowires (NWs) was prepared through a sequential low-temperature hydrothermal-growth process. The devices that were annealed in an oxygen (O 2) ambient exhibited better rectification behavior (I forward/I reverse = 427), a lower forward threshold voltage (V th = 0.98 V), a lower leakage current (1.68 × 10 -5 A/cm 2), and superior sensitivity (I UV/I dark = 57-8; Ivisible/Idark = 1 -25) to UV light (λ = 325 nm) than the unannealed devices. The remarkably improved device performances and optoelectronic characteristics of the annealed p-NiO-NF/n-ZnO-NW NHJs can be associated with their fewer structural defects, fewer interfacial defects, and better crystallinity A stable and repeatable operation of dynamic photoresponse was also observed in the annealed devices. The excellent sensitivity and repeatable photoresponse to UV light of the hydrothermally grown p-NiO-NF/n-ZnO-NW NHJs annealed in a suitable O 2 ambient indicate that they can be applied to nano-integrated optoelectronic devices.
- Hydrothermal Method
- Nanoflower (NF)
- Nanoheterojunction (NHJ)
- Nanowire (NW)
- Ultraviolet (UV) Photodetector