Surface Acoustic Wave Sensors Based on Nanoporous Films for Hydrogen Detection

Abstract:

Surface Acoustic Wave Sensor is one of the most promising detection systems due tosmaller size, lower weight, power requirements and great sensitivity. It is known from the liter-ature that Pd and ZnO are the most promising materials for detecting hydrogen. A nanoporousPd and ZnO based layered SAW sensors have been developed and investigated for hydrogen,at room temperature. The sensors were of a delay line type (quartz substrate, 70 MHz cen-tral frequency). The nanoporous sensitive layer was directly deposited onto a quartz substrateusing a picosecond laser ablation method. Lasers with picosecond pulses or a high repetitionrate leads to major changes in the ablation process and implicit in the deposited lm struc-ture. Thus, using such a regime, at a certain ambient gas pressure, we have the advantage ofdirectly obtaining a nanoporous lm. The sensor performances (sensitivity, limit of detectionand response time), for a hydrogen concentration in synthetic air of 0.015 2 % were studied.For a concentration between 0.2 - 0.8 % hydrogen/synthetic airs, the response times was 15 -44 s and 6 - 27 s in case of Pd lms and ZnO respectively. Limit of detection was about 6.3times better at Pd sensors (50 ppm) than ZnO sensors (315 ppm).

• Periodical: Key Engineering Materials (Volume 605)
• Pages: 331-334
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.605.331
• Online since: April 2014
• Authors: Cristian Viespe
• Keywords: Hydrogen Sensor, Nanoporous Film, Pd, Picosecond Laser Ablation, SAW Sensors, ZNO

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