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

José Ramón Durán 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

48 Scopus citations

Abstract

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
Pages (from-to)354-359
Number of pages6
JournalACS Photonics
Volume1
Issue number4
DOIs
StatePublished - 16 Apr 2014

Keywords

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

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