Hydrogen sensing behavior of palladium porous silicon silicon diodes. Effect of anodization time

The properties of Palladium / Porous silicon (PS) / Silicon diodes and their use for the detection of hydrogen are described. The current-voltage (I-V) curves exhibit a good rectifying behavior. The forward I-V characteristics approach standard diode behavior, but with a large diode duality factor in air, n>>1. In hydrogen ambient of 1, 10, 100%, the I-V curves shift to an increase in current and exhibit a strong hydrogen-induced decrease in the diode quality factor. Depending on the anodization time of the PS layer, the hydrogen-induced voltage shift determined at a constant current, shows a value of Delta V-H = 0.5 to 2.8 V, which is very large in comparison to that of a Pd-Si Schottky diode. The response time strongly depends on the anodization time.