Low Power Hydrogen Sensors Using Electrodeposited PdNi Schottky Diodes

Usgaocar, Ashwin, de Groot, Kees, Boulart, C. and Chavagnac, V.M.C. (2010) Low Power Hydrogen Sensors Using Electrodeposited PdNi Schottky Diodes. Eursosensors, Linz, Austria. (In Press)

Abstract

The use of electrodeposited PdNi Schottky barriers as low power Hydrogen sensors is investigated. Electrodeposited PdNi Schottky barriers exhibit very low reverse bias current and the Palladium content of the film causes the Hydrogen molecules to dissociate and be absorbed by the film, changing the metal work function and device current. The Schottky diodes were fabricated on 0.5-1.5 Ohmcm (100) n-type Si by electrodeposition of PdNi followed by evaporation of Aluminium contact pads. Electrical measurements at different Hydrogen pressures were performed on back to back Schottky diodes in a vacuum chamber using pure Nitrogen and a 5% Hydrogen-Nitrogen mixture. Very low currents of 1nA were measured in the absence of Hydrogen. Large increases in the currents, upto a factor of 100, were observed upon exposure to different Hydrogen partial pressures. The highest sensitivity was estimated to be 17.27 nA/mbar. The low idle current, simplicity of fabrication process and ability to easily integrate with conventional electronics proves the suitability of electrodeposited PdNi Schottky barriers as low power Hydrogen sensors.

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Contributors

Author: Kees de Groot

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