Development of gas sensors based on tungsten oxide nanowires in metal/SiO2/metal structure and their sensing responses to NO 2

Rong Ming Ko, Shui Jinn Wang, Zhi Fu Wen, Jun Ku Lin, Ga Hong Fan, Wen I. Shu, Bor Wen Liou

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

In this work, the fabrication of gas sensors utilizing self-synthesized tungsten oxide nanowires (TONWs) and their response to NO2 are reported. The gas sensor is based on a sputter-deposited WCx/SiO 2/WCx triple-layer structure with the periphery of the SiO2 layer etched chemically. Self-synthesized TONWs with crystalline W18O49(010) were grown by simple thermal annealing in nitrogen ambient, which linked, in parallel, the upper and lower WCx electrodes for gas sensing. The TONW-based sensors increased in resistance in NO2 because the surface of TONWs comprised oxygen adsorbates and the adjacent space charge region was electron-depleted. The amount of enlargement in resistance increased with increasing temperature. To improve the detectability of the parallel-connected TONW-based sensor, a connection of several individual sensors in series was proposed to enlarge the number of TONWs for gas sensing. For the 8-series-connected sensor, a sensitivity as high as 9.3. a response time as low as about 9 s, and a detectability as low as 2 ppm for NO2 were obtained.

Original languageEnglish
Pages (from-to)3272-3276
Number of pages5
JournalJapanese Journal of Applied Physics
Volume47
Issue number4 PART 2
DOIs
Publication statusPublished - 2008 Apr 25

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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