1INTERFACIAL STABILITY OF THIN FILM HYDROGEN SENSORS

The real and perceived hazards of hydrogen fuel use, its production, and storage require extensive safety precautions and codes to be put in place before any serious movement can be made towards a hydrogen based energy future. Currently, commercial hydrogen detectors are not useful for widespread use, particularly in transportation, because they are too bulky, expensive, and dangerous. Recent work sponsored by the DOE Hydrogen Program has developed promising technologies for satisfying the future demands. Sensors that exhibit physical or optical changes when exposed to hydrogen have been fabricated and tested, and promise to provide inexpensive hydrogen detection. For example, there are thick film and thin film metallic sensors that exhibit a conductivity change when hydrogen adsorbs on the surface and is incorporated into the lattice. There are thin film sensors that are deposited as a part of a field-effect transistor, where accumulation of atomic hydrogen at the metal/insulator interface results in a change of response from the circuit. Finally, there are chemochromic sensors, where reaction of thin films with hydrogen gas results in an optical change that can be sensed by a probe beam of light. All of these sensors have the potential for degradation in their performanc