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 language | English |
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Pages (from-to) | 357-363 |
Number of pages | 7 |
Journal | Sensors and Actuators, B: Chemical |
Volume | 160 |
Issue number | 1 |
DOIs | |
Publication status | Published - 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