Hydrogen Detection with Semimetal Graphite-ZnO (InP,GaN) Schottky Diodes

We investigated Schottky diode hydrogen sensors prepared by printing colloidal graphite on ZnO, GaN, and InP substrates partly covered with Pt nanoparticles. A layer of Pt nanoparticles deposited by in-situ pulsed electrophoretic deposition from isooctane colloidal solutions was inserted between the semimetal graphite and the semiconductor surface to dissociate hydrogen molecules. Schottky diodes were investigated by the measurement of current-voltage characteristics and further tested for their sensitivity to hydrogen in a cell with a through-flow gas system. The sensing elements were sensitive to gas mixture with a low hydrogen concentration down to 1 ppm.