Wide-range (0.33%–100%) 3C–SiC resistive hydrogen gas sensor development

Silicon carbide (SiC) resistive hydrogen gas sensors have been fabricated and tested. NiCr planar ohmic contacts were deposited on both a 4μm 3C–SiC epitaxial film grown on n-type Si(001) and directly on Si to form the resistive sensor structures. Detection at concentrations as low as 0.33% and as high as 100% (H2 in Ar) was observed with the 3C–SiC sensor while the Si sensor saturated at 40%. The 3C–SiC sensors show a remarkable range of sensitivity without any saturation effects typically seen in other solid-state hydrogen gas sensors. Under a constant 2V bias, these sensors demonstrated an increase in current up to 17mA upon exposure to pure H2. Preliminary experiments aimed at determining the gas sensing mechanism of these devices have been conducted and are also reported.