SAW sensor based on highly sensitive nanoporous palladium thin film for hydrogen detection
Surface acoustic wave sensors (SAWSs) with nanoporous palladium (Pd) sensing material for hydrogen (H2) detection are reported. We fabricated sensors with a stable and fast response and with a high sensitivity for detecting H2 even at room temperature (RT). The fabricated sensors were delay line type (quartz substrate, ?70MHz central frequency). The nanoporous sensitive layer was directly deposited onto a quartz substrate using the picosecond laser ablation method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the influence of different experimental conditions, such as laser power density and inert gas pressure, on the morphological proprieties of Pd thin films. The sensor performance (sensitivity, detection limit, and response time) at RT, for H2 concentrations in synthetic air between 0.008% and 2% were studied. We obtained a sensitivity and detection limit of 0.31Hz/ppm and 48ppm, respectively, for RT operation. The response time was between 15 and 44s for H2 concentrations between 0.2% and 0.8% in synthetic air.
saw sensor palladium hydrogen sensor nanoporous film pulsed laser deposition