A novel high-sensitive Pd/InP hydrogen sensor fabricated by electroless plating

In this work, a novel electroless plating technique was proposed to fabricate high-sensitive Pd/InP Schottky diode hydrogen sensors. The Schottky current-voltage (I-V characteristics were investigated at hydrogen concentrations in air ranging from 15-10,000 ppm. Experimental results show that the Schottky diode characteristics for the sensor devices obtained by electroless plating are superior to those obtained by the conventional thermal evaporation. Furthermore, due to the low-energy fabrication, the Fermi-level pinning effect can be avoided and therefore, the sensor device exhibits high sensitivity on hydrogen. Even at very low hydrogen concentration of 15 ppm, the saturation sensitivity reaches about 2.07. Further analyzing the I-V data, it shows that the experimental results are in a good agreement with the proposed hydrogen adsorption model. (C) 2002 Elsevier Science B.V. All rights reserved.