Electrical and photoelectric properties of a Pd-p 0-Si-p-Si structure with a disordered intermediate p 0 layer

Abstract

The electrical characteristics and the photovoltage on Pd-p 0-Si-p-Si diode structures with a disordered (porous) p 0 layer of Si have been measured. The current-transfer mechanism is assumed to be double injection of electrons and holes into the p 0 layer. In a hydrogen atmosphere, the photovoltage increases by a factor of 20 and the reverse current falls by a factor of 3–4. The increase of the photovoltage is associated with the growth of a Pd-p 0-Si Schottky barrier, while the decrease of the dark current is attributable to the variation in the amount of injected electrons. The relaxation of the photovoltage after turning off the H2 flow has two time intervals, with lengths of about 130 and 420 sec. It is shown that these features of the relaxation are associated with heterogeneity of the structure of the p 0 layer, which includes unanodized sections and porous sections. These regions of the structure each contain their own set of deep traps and recombination centers. This set of traps and recombination centers can vary as a result of the introduction of hydrogen which creates induced “temporary” deep levels.