Effect of oxygen annealing on the ultraviolet photoresponse of p-NiO-nanoflower/n-ZnO-nanowire heterostructures

Po Yu Yang*, Jyh Liang Wang, Wei Chih Tsai, Shui Jinn Wang, Jia Chuan Lin, I. Che Lee, Chia Tsung Chang, Huang-Chung Cheng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


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.

Original languageEnglish
Pages (from-to)5737-5743
Number of pages7
JournalJournal of Nanoscience and Nanotechnology
Issue number7
StatePublished - 1 Jul 2011


  • Hydrothermal Method
  • Nanoflower (NF)
  • Nanoheterojunction (NHJ)
  • Nanowire (NW)
  • Ultraviolet (UV) Photodetector

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