Abstract
Detection of hydrogen gas is a crucial task for establishing safety and reliability of fuel cells, a key technology for the environment and our society. However, hydrogen is difficult to detect and various hydrogen sensors have many drawbacks. Here we report a novel hydrogen gas sensor, the ball surface acoustic wave (SAW) sensor, using Pd or PdNi sensitive film. The ball SAW sensor is based on a novel phenomenon, diffraction-free propagation of collimated beam along an equator of sphere. The resultant ultra-multiple roundtrips of SAW makes it possible to achieve highest sensitivity among SAW sensors. Moreover, it enables to use a very thin sensitive film, and consequently the shortest response time (2s) was realized. In terms of the sensing range, it has the widest range of 10 ppm to 100% among any hydrogen sensors including FET or resistivity sensors. The ball SAW sensor can be applied not only to hydrogen but also to any gasses and possibly to liquids.
| Original language | English |
|---|---|
| Pages (from-to) | 48-52 |
| Number of pages | 5 |
| Journal | Key Engineering Materials |
| Volume | 321-323 I |
| DOIs | |
| Publication status | Published - 2006 Jan 1 |
Keywords
- Explosive limit
- Fuel cells
- Hydrogen gas
- Naturally collimated beam
- SAW sensor
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering