Transparent conducting oxide electrodes for novel metal oxide gas sensors

  • Young Seok Shim
  • , Hi Gyu Moon
  • , Do Hong Kim
  • , Ho Won Jang*
  • , Chong Yun Kang
  • , Young Soo Yoon
  • , Soek Jin Yoon
  • *Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    31 Citations (Scopus)

    Abstract

    We report fabrication and gas sensing properties of semiconducting metal oxide gas sensors using conducting oxide electrodes. Indium-tin oxide (ITO) and aluminum-doped zinc oxide (AZO) films are used to replace Pt electrodes in WO3 or SnO2 thin-film gas sensors. Before and after thermal annealing at 300 °C for 3200 min, the resistivity of the ITO film increases from 1.3 × 10-4 to 7.0 × 10-4 Ω cm, whereas the AZO film shows a significant increase in resistivity from 2.0 × 10-3 to 5.1 × 101 Ω cm due to the annihilation of oxygen vacancies in the film. Upon exposure to 50 ppm CO at 300 °C, WO3 or SnO2 thin-film sensors with ITO interdigitated electrodes (IDEs) on glass substrates display higher responses than sensors with Pt IDEs, attributed to the low-resistance ohmic contacts between the electrode (ITO) and the sensing material (WO3 or SnO 2). The reproducible response, the concentration-dependent modulation in sensitivity, and a sub-ppm detection limit indicates the reliable operation of sensors made with ITO IDEs. The high transmittance, exceeding 75%, of the sensors at visible wavelengths holds promise for future applications to transparent gas sensors.

    Original languageEnglish
    Pages (from-to)357-363
    Number of pages7
    JournalSensors and Actuators, B: Chemical
    Volume160
    Issue number1
    DOIs
    Publication statusPublished - 2011 Dec 15

    Bibliographical note

    Funding Information:
    This work was financially supported by the Core Technology of Materials Research and Development Program of the Korea Ministry of Intelligence and Economy (Grant No. K0004114 ) and a KIST research program (Grant No. 2E22121).

    Keywords

    • Aluminum-doped zinc oxide
    • Gas sensors
    • Indium-tin oxide
    • Ohmic contact
    • Transparent conducting oxides

    ASJC Scopus subject areas

    • 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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