Micro-machined thin film sensor arrays for the detection of H2 containing gases, and method of making and using the same

A method of fabricating a hydrogen sensor on a substrate, comprising:

• constructing on the substrate a micro-hotplate structure;
• and
• forming on the micro-hotplate structure a hydrogen-interactive thin film comprising a rare earth metal and/or a rare earth metal dihydride that upon exposure to hydrogen exhibits a detectable change of at least one physical property, and wherein the hydrogen-interactive thin film is arranged to be heated by the micro-hotplate structure;
• and
• forming on the hydrogen-interactive thin film a protective over layer comprising a hydrogen-permeable material for selective permeation of hydrogen, wherein said hydrogen-permeable material comprises an alloy to suppress a phase change in said rare earth metal or rare metal dihydride.

A hydrogen sensor, comprising:

• at least one hydrogen-interactive thin film sensor element comprising a rare earth metal or a rare metal dihydride, which exhibits a detectable change of physical property when exposed to hydrogen;
• a hydrogen-permeable material overlaying each hydrogen-interactive element for selective permeation of hydrogen, wherein said hydrogen-permeable material comprises an alloy containing at least one metal element selected from the group consisting of titanium and nickel;
• and
• a detector constructed and arranged for detecting said detectable change of physical property exhibited by said rare earth metal or rare earth metal dihydride upon exposure to hydrogen.