Influence of hydrogen on the impedance of Pd/oxide/InP structures

The impedance and capacitance properties of Pd/oxide/InP structures within the frequency range from 0.1 Hz to 10 kHz in air and in gaseous hydrogen–nitrogen mixture at 300 K have been studied. The characteristics of investigated structures can be characterized by parallel RC circuit model with the connected serial resistance. In hydrogen medium the active resistance of the structures decreases by 3 orders of magnitude and the capacitance increases by 1–3 orders of magnitude depending on frequency that is due probably to the positive charged centers formed in the oxide layer. In hydrogen medium the hysteresis has been found on CV-characteristics of the structures that may be explained by ion polarization of formed centers. It is shown that measured in electron units the full charge of the centers practically coincides with the quantity of hydrogen atoms absorbed by palladium.