Concurrent Improvement in Photogain and Speed of a Metal Oxide Nanowire Photodetector through Enhancing Surface Band Bending via Incorporating a Nanoscale Heterojunction

Jose Ramon Duran Retamal, Cheng Ying Chen, Der Hsien Lien, Michael R.S. Huang, Chin An Lin, Chuan Pu Liu, Jr-Hau He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


The surface effect on the photodetection of metal oxide nanostructures acting as a double-edged sword achieves ultrahigh photogain but unavoidably prolongs the response time due to slow oxygen adsorption/desorption processes. In this study, we break the compromise to enhance the UV photogain by 3 orders of magnitude as well as increase the photoresponse speed by 5 times via incorporating open-circuit p-n nanoscale heterojunctions (NHJs) by forming single-crystalline p-NiO nanoparticles on n-ZnO nanowires. This is because the formation of NHJs enhances surface band bending of ZnO nanowires, improving the spatial separation efficiency of photogenerated electrons and holes, and passivates the ZnO surfaces by minimizing the interaction of photocarriers with chemisorbed oxygen molecules. The concept using NHJs explores a new pathway toward ultrafast and supersensitive photodetection. (Graph Presented).

Original languageEnglish (US)
Pages (from-to)354-359
Number of pages6
JournalACS Photonics
Issue number4
StatePublished - Apr 16 2014


  • ZnO
  • nanowire
  • photodetector
  • surface band bending
  • surface effect

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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