Dielectrophoretic fabrication and characterization of a ZnO nanowire-based UV photosensor

Junya Suehiro, Nobutaka Nakagawa, Shin Ichiro Hidaka, Makoto Ueda, Kiminobu Imasaka, Mitsuhiro Higashihata, Tatsuo Okada, Masanori Hara

Research output: Contribution to journalArticle

213 Citations (Scopus)

Abstract

Wide-gap semiconductors with nanostructures such as nanoparticles, nanorods, nanowires are promising as a new type of UV photosensor. Recently, ZnO (zinc oxide) nanowires have been extensively investigated for electronic and optoelectronic device applications. ZnO nanowires are expected to have good UV response due to their large surface area to volume ratio, and they might enhance the performance of UV photosensors. In this paper, a new fabrication method of a UV photosensor based on ZnO nanowires using dielectrophoresis is demonstrated. Dielectrophoresis (DEP) is the electrokinetic motion of dielectrically polarized materials in non-uniform electric fields. ZnO nanowires, which were synthesized by nanoparticle-assisted pulsed-laser deposition (NAPLD) and suspended in ethanol, were trapped in the microelectrode gap where the electric field became higher. The trapped ZnO nanowires were aligned along the electric field line and bridged the electrode gap. Under UV irradiation, the conductance of the DEP-trapped ZnO nanowires exponentially increased with a time constant of a few minutes. The slow UV response of ZnO nanowires was similar to that observed with ZnO thin films and might be attributed to adsorption and photodesorption of ambient gas molecules such as O2 or H 2O. At higher UV intensity, the conductance response became larger. The DEP-fabricated ZnO nanowire UV photosensor could detect UV light down to 10nWcm-2 intensity, indicating a higher UV sensitivity than ZnO thin films or ZnO nanowires assembled by other methods.

Original languageEnglish
Pages (from-to)2567-2573
Number of pages7
JournalNanotechnology
Volume17
Issue number10
DOIs
Publication statusPublished - May 28 2006

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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