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A. Romano-Rodriguez, J. Sama, J. Prades, O. Casals, F. Hernandez-Ramirez, S. Barth:
"Ultralow power gas sensor based on SnO₂ selfheated nanowires";
Poster: 2014 EMRS Spring Meeting, Lille, France; 2014-05-25 - 2014-05-29; in: "2014 EMRS Spring Meeting - PROGRAM VIEW", (2014).

Semiconducting nanowires (NW) are very attractive materials for gas sensing applications due to their high aspect ratio, that results in strong interactions between their surface and the surrounding atmosphere, giving rise to important electrical changes in the nanomaterial. Heating the NW is required to reach the right operation temperature. When operating with one single NW, the same current that is used to measure the resistance can be used to provide the NW heating, dramatically reducing the power consumption of the device. Here we present a single metal oxide nanowire gas sensor with ultra low power consumption based on this principle. Defect-free monocrystalline SnO2 nanowires were synthesized by chemical vapor deposition of a molecular precursor [Sn(OtBu)4]. NWs were dispersed onto a substrate with prepatterned electrodes and a Focused Ion Beam machine equipped with a Pt precursor was used to contact the individual NW to the electrodes. Very low level of currents, below of 1 µA, are enough to bring the nanomaterial to temperatures in excess of 150ºC, at which the reaction between surface adsorbed oxygen and reducing or oxidizing species takes place, while allowing the resistance variation to be measured. High response and low response times have been obtained against NO2, and a mixture of NO2 with humidity in a synthetic air atmosphere. The advantages and drawbacks of the approach to develop these advanced ultra-low power consumption gas sensors will be discussed.