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Detail
Journal Article
Encapsulation of Semiconductor Gas Sensors with Gas Barrier Films for USN Application
- Authors
- Hyung-Kun Lee, Woo Seok Yang, Nak-Jin Choi, Seung Eon Moon
- Issue Date
- 2012-10
- Citation
- ETRI Journal, v.34, no.5, pp.713-718
- ISSN
- 1225-6463
- Publisher
- 한국전자통신연구원 (ETRI)
- Language
- English
- Type
- Journal Article
- Abstract
- Sensor nodes in ubiquitous sensor networks require autonomous replacement of deteriorated gas sensors with reserved sensors, which has led us to develop an encapsulation technique to avoid poisoning the reserved sensors and an autonomous activation technique to replace a deteriorated sensor with a reserved sensor. Encapsulations of In 2O 3 nanoparticles with poly(ethylene-co-vinyl alcohol) (EVOH) or polyvinylidene difluoride (PVDF) as gas barrier layers are reported. The EVOH or PVDF films are used for an encapsulation of In 2O 3 as a sensing material and are effective in blocking In 2O 3 from contacting formaldehyde (HCHO) gas. The activation process of In 2O 3 by removing the EVOH through heating is effective. However, the thermal decomposition of the PVDF affects the property of the In 2O 3 in terms of the gas reactivity. The response of the sensor to HCHO gas after removing the EVOH is 26%, which is not significantly different with the response of 28% in a reference sample that was not treated at all. We believe that the selection of gas barrier materials for the encapsulation and activation of In 2O 3 should be considered because of the ill effect the byproduct of thermal decomposition has on the sensing materials and other thermal properties of the barrier materials. © 2012 ETRI.
- KSP Keywords
- Activation process, Activation technique, Barrier materials, Encapsulation technique, Gas barrier films, O 3, PVDF film, Polyvinylidene difluoride(PVDF), Semiconductor gas sensor, Sensing material, Sensor node