Influence of Hydrogen on the Electrical Properties of Pd/InP Structures

Abstract

The influence of hydrogen on the electrical properties of Pd/n-InP and Pd/oxide/n-InP structures is studied. It is found that a variation in the cutoff voltage $$\Delta {{U}_{{{\text{cut-off}}}}}$$ in the current–voltage characteristics of the structures under study upon exposure to hydrogen with concentrations of 0–1 vol % in a nitrogen–hydrogen mixture is described by the exponential dependence: $$\Delta {{U}_{{{\text{cut-off}}}}}$$ = a[1 – exp(–b ⋅ NH)], where NH is the hydrogen concentration (vol %), and a and b are constants dependent on the type of structures. It is shown that a decisive influence on how the potential-barrier height changes in the Pd/InP and Pd/oxide/InP structures in the presence of H2 in a gas medium is exerted by a change in the Pd work function in an atmosphere of hydrogen. It is found that, in the structures under study, tunneling and thermal-tunneling charge-transport mechanisms operate at 90–300 K in the presence of hydrogen and without it. With increasing hydrogen concentration in the gas mixture, the predominance of the tunneling charge-transport mechanism becomes more pronounced.