Ultraviolet photodetectors using hollow p-CuO nanospheres/n-ZnO nanorods with a pn junction structure

Yuexing Ji, Uijin Jung, Zhanpeng Xian, Dohyun Kim, Jiyeon Yu, Jinsub Park

Research output: Contribution to journalArticle

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Abstract

We report on ultraviolet (UV) photodetectors with a pn junction structure consisting of hollow p-CuO (h-CuO) nanospheres and n-ZnO nanorods (NRs). To form the pn junction structure, thermal annealing was conducted using a transferred monolayer of Cu-ion-incorporated polymer spheres onto the n-ZnO NRs/n-Si substrate. Device performance was evaluated by comparing the effects of h-CuO nanosphere coverage changed by sphere shrinkage during thermal annealing of Cu-ion-incorporated polymer spheres. Three samples were prepared by varying the transfer times of h-CuO on ZnO NRs: 0 times (Reference), 1 time (CZ-I), and 2 times (CZ-II). The CZ-II-based UV detector shows a fast rising time of 1.8 s and a falling time of 0.26 s, which are faster rising by 2.2 and 1.3 times and faster falling by 3.1 and 32.6 times than those of the CZ-I and Reference UV detectors, respectively, under illumination with UV light at 254 nm. Moreover, the On/Off current ratio of the CZ-II UV detector is 4.58, which is about 3.3 times and 3.5 times higher than that of the CZ-I and Reference devices, respectively. The higher h-CuO coverage on the ZnO NRs that form the pn junction structure can effectively separate the electron and hole and suppress recombination by mutual transfer of photo-generated electrons and holes in the heterojunction.

Original languageEnglish
Article number111876
JournalSensors and Actuators, A: Physical
Volume304
DOIs
StatePublished - 2020 Apr 1

Keywords

  • Hollow CuO
  • Transfer of spheres monolayer
  • UV detector
  • ZnO

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