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Author: search.filters.author.Benedict, SamathaSubject: search.filters.subject.Gas sensor

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    Plasma Oxidized Suspended Core-Shell Nanostructures for High Performance Metal Oxide Gas sensors
    (IEEE, 2019) Benedict, Samatha
    We report on the novel technique of creating core-shell metal-metal oxide high performance gas sensors using plasma oxidation of a suspended metal thin film. We demonstrate that this technique is very generic by realizing Pt-PtOx and W-WOx nanostructured sensors. The optimization technique for plasma oxidation is elucidated. We also propose an improvisation technique to create nano discs on top of suspended core-shell metal-metal oxide sensor to further enhance the performance.
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    Low power gas sensor array on flexible acetate substrate
    (IOP, 2017-06) Benedict, Samatha
    In this paper, we present a novel approach of fabricating a low-cost and low power gas sensor array on flexible acetate sheets for sensing CO, SO2, H2 and NO2 gases. The array has four sensor elements with an integrated microheater which can be individually controlled enabling the monitoring of four gases. The thermal properties of the microheater characterized by IR imaging are presented. The microheater with an active area of 15 µm  ×  5 µm reaches a temperature of 300 °C, consuming 2 mW power, the lowest reported on flexible substrates. A sensing electrode is patterned on top of the microheater, and a nanogap (100 nm) is created by an electromigration process. This nanogap is bridged by four sensing materials doped with platinum, deposited using a solution dispensing technique. The sensing material characterization is completed using energy dispersive x-ray analysis. The sensing characteristics of ZnO for CO, V2O5 for SO2, SnO2 for H2 and WO3 for NO2 gases are studied at different microheater voltages. The sensing characteristics of ZnO at different bending angles is also studied, which shows that the microheater and the sensing material are intact without any breaking upto a bending angle of 20°. The ZnO CO sensor shows sensitivity of 146.2% at 1 ppm with good selectivity.