Schottky-type response of carbon nanotube NO 2 gas sensor fabricated onto aluminum electrodes by dielectrophoresis

Junya Suehiro, Hiroshi Imakiire, Shin Ichiro Hidaka, Weidong Ding, Guangbin Zhou, Kiminobu Imasaka, Masanori Hara

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Abstract

Single-walled carbon nanotube (CNT) gas sensors were fabricated by dielectrophoresis onto microelectrodes made of Cr, Pd or Al. The Al/CNT sensor response to NO 2 (nitrogen dioxide) gas was characterized by fast and large resistance increase at the moment of NO 2 exposure, whereas the resistance of the other metal/CNT sensors monotonously decreased. It was suggested that the adsorbed NO 2 molecules might alter the Schottky barrier at the Al/CNT interface as well as the positive hole density in the p-type semiconducting CNT. The Al/CNT sensor response could be interpreted as a superposition of the Schottky contact resistance and the CNT resistance, which were differently influenced by the NO 2 adsorption and contributed to the overall sensor response. The Schottky response of the Al/CNT sensor was approximately one order of magnitude faster than the CNT response obtained using the other metal electrodes.

Original languageEnglish
Pages (from-to)943-949
Number of pages7
JournalSensors and Actuators, B: Chemical
Volume114
Issue number2
DOIs
Publication statusPublished - Apr 26 2006

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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