Wide dynamic range hydrogen sensing using silver-rutile Schottky diode

The hydrogen sensitivity of the reverse current in silver-rutile Schottky diode is investigated. Sample devices were prepared by the partial sintering of silver particles on thermally oxidized titanium foil. The device exhibited Schottky-type current-voltage characteristics in the 200 to 400degC operating temperature range in clean air. The high sensitivity and wide dynamic range observed for hydrogen detection are described by a model based on the variation of the height of the potential barrier established at the junction with respect to the concentration of the reducing contaminations in the surrounding atmosphere, which reduced the adsorbed oxygen coverage at the effective surface of the silver aggregate. The wide dynamic range of the device allowed a single sensor to measure H₂ contamination in air in 50 ppm to 25% range.