In this project a Surface Acoustic Wave Sensor (SAWS) was developed with nanostructure film for hydrogen detection at room temperature (RT) with improved limit of detection (LOD), response and recovery time. Various types of sensor technologies for hydrogen detection have been developed and utilized, but, the fast and precise detection of the presence of hydrogen, especially before reaching the explosive concentration at RT, is still a problem. As a sensitive layer we have chosen nanoporous films such as WO3, Pd and ZnO for their good hydrogen detection results imprinted with waveguide channels. Different configurations of channels for guiding the waves between interdigital transducers, in order to minimize the spurious wavefront, were designed, studied and optimized .
The nanoporous films and waveguides channels were done by a laser ablation method using a picosecond laser. This new proposed sensing configuration (waveguide channels), on the one hand, improved the signal-to-noise ratio, and on the other hand, was decreased the signal energy loss.
To the best of our knowledge,it is for the first time when this new approach of the SAWS sensing layer is proposed, with considerable improvement on the acoustic wavefront, aiming the final goal of enhancing LOD, response and recovery time. SAWS performances and correlations between materials, porosity and channels configuration of film were studied, selecting the best configuration for RT hydrogen detection.