Thin films of Pd/Ni alloys for detection of high hydrogen concentrations

Thin alloy films of Pd and Ni (8%<Ni<20% in at. %) formed by dual‐electron‐beam evaporation techniques have been found to give durable and quickly reversible detectors of high H₂ concentrations (pH₂ 0.1%–100%, 0.7–700 Torr) near 1 atm and 300 K, including accurate determinations of pH₂ around the lower explosive limit of 4% in air. The addition of Ni suppresses the α to β phase transition found in pure Pd under these conditions. The measurement of resistivity changes in the thin films along with flatband shifts of metal‐oxide‐semiconductor capacitors on the same Si wafer gives accurate values of pH₂ over more than six decades.