TY - JOUR
T1 - Development of gas sensors based on tungsten oxide nanowires in metal/SiO2/metal structure and their sensing responses to NO 2
AU - Ko, Rong Ming
AU - Wang, Shui Jinn
AU - Wen, Zhi Fu
AU - Lin, Jun Ku
AU - Fan, Ga Hong
AU - Shu, Wen I.
AU - Liou, Bor Wen
PY - 2008/4/25
Y1 - 2008/4/25
N2 - 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.
AB - 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.
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U2 - 10.1143/JJAP.47.3272
DO - 10.1143/JJAP.47.3272
M3 - Article
AN - SCOPUS:54249104514
VL - 47
SP - 3272
EP - 3276
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 4 PART 2
ER -