Influence of humidity and hydrogen on the charge transport in p-InP diode structures with a palladium contact

Abstract

The p-InP-n-In2O3-P2O5-Pd diode structure was fabricated using a two-stage technological procedure, which involved cold etching, polishing, and electrochemical deposition of palladium. The charge transport is investigated in the temperature range of 110–300 K, and the current-voltage characteristics are explained in terms of tunneling through a barrier, over deep trapping centers, and band-to-band tunneling. It is found that the open-circuit photovoltage increases in a water vapor atmosphere. It is demonstrated that this effect is defined by the variation of the recombination kinetics via bound states on the n-In2O3-P2O5 heteroboundary because of the absorption of H2O molecules in P2O5 oxide. The open-circuit photovoltage increases linearly with the water vapor concentration, and the relaxation of the photovoltage pulse takes ∼1–2 s. Photovoltage relaxation for the forward and reverse currents after the action of H2 is investigated. The data obtained revealed the possibility of devising a detector of threefold application, namely, for detecting near-infrared radiation, humidity, and hydrogen.