Fabrication of thin sensitive film of ball surface acoustic wave sensor by off-axis spin-coating method

Kentaro Kobari, Yutaro Yamamoto, Masanori Sakuma, Shingo Akao, Toshihiro Tsuji, Kazushi Yamanaka

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


In environmental assessment and security, it is necessary to detect hazardous gases at low concentrations. The ball surface acoustic wave (SAW) sensor can have significantly improved sensitivity when the ultramultiple roundtrips (e.g., >100 turns) of the SAW is achieved. However, it is hindered by the thick and coarse organic sensitive film fabricated by the conventional spin-coating method. We propose an "off-axis spin coating method" in order to fabricate thin and highly uniform organic sensitive film with high reproducibility. Langasite ball SAW sensors were coated by polyisoprene, polyisobutylene, and polydimethylsiloxane sensitive films and were applied in detecting normal saturated hydrocarbons (pentane, hexane, heptane, octane, and nonane), a nerve gas simulant (dimethyl methylphosphonate: DMMP), and sick-house gases (benzene, toluene, and xylene). With the proposed method, we succeeded in realizing multiple roundtrips and in detecting DMMP at a sub-ppm concentration without preliminary condensation of the sample.

Original languageEnglish
Article number07GG13
JournalJapanese journal of applied physics
Issue number7 PART 2
Publication statusPublished - 2009 Jul 1
Externally publishedYes

ASJC Scopus subject areas

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


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