Influence of Hydrogen on the Impedance of Pd/Oxide/InP Structures

The impedance and capacitive properties of Pd/oxide/InP structures are investigated at 300 K in the frequency range of 10 –1 –10 –5 Hz in air and in a nitrogen–hydrogen gas medium. The characteristics of structures in both media are interpreted based on a parallel RC -chain model with series resistance. The structure resistance decreases in the presence of hydrogen by three orders of magnitude, while the capacitance increases by 1–3 orders of magnitude depending on the frequency, which is possibly associated with the formation of positively charged centers in the oxide. Hysteresis is found in the capacitance–voltage characteristics in the medium with hydrogen, which is possibly caused by the ionic polarization of centers. It is shown that the total charge of centers measured in units of electrons almost coincides with the number of hydrogen atoms absorbed by palladium.