Electrostatically gated graphene-zinc oxide nanowire heterojunction

Xueqiu You, James Jungho Pak

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


This paper presents an electrostatically gated graphene-ZnO nanowire (NW) heterojunction for the purpose of device applications for the first time. A sub-nanometer-thick energy barrier width was formed between a monatomic graphene layer and electrochemically grown ZnO NWs. Because of the narrow energy barrier, electrons can tunnel through the barrier when a voltage is applied across the junction. A near-ohmic current-voltage (I-V) curve was obtained from the graphene-electrochemically grown ZnO NW heterojunction. This near-ohmic contact changed to asymmetric I-V Schottky contact when the samples were exposed to an oxygen environment. It is believed that the adsorbed oxygen atoms or molecules on the ZnO NW surface capture free electrons of the ZnO NWs, thereby creating a depletion region in the ZnO NWs. Consequentially, the electron concentration in the ZnO NWs is dramatically reduced, and the energy barrier width of the graphene-ZnO NW heterojunction increases greatly. This increased energy barrier width reduces the electron tunneling probability, resulting in a typical Schottky contact. By adjusting the back-gate voltage to control the graphene-ZnO NW Schottky energy barrier height, a large modulation on the junction current (on/off ratio of 103) was achieved.

Original languageEnglish
Pages (from-to)2040-2046
Number of pages7
JournalJournal of Nanoscience and Nanotechnology
Issue number3
Publication statusPublished - 2015 Jan 1


  • Graphene-ZnO NWs heterojunctions
  • Schottky barrier
  • Three-terminal operation
  • Tunneling barrier

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics


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