EFFECT OF PT LAYERS ON THE PHOTOELECTROCHEMICAL PROPERTIES OF A WO3 P-SI ELECTRODE/

The effect of Pt deposition on the photoelectrochemical properties of a WO3/p-Si electrode was studied with regard to hydrogen evolution, ph otocurrent transient, and chemical stability. Deposition of Pt layers made it possible for photocurrent onset potential to be shifted to a m ore positive value and both the photocurrent density and hydrogen evol ution rate were increased. These phenomena can be explained by the fac t that Pt loading decreases the overpotentials in the reduction reacti on at the electrode/electrolyte interfaces to make electron transfer f aster, as well as decrease the recombination rate of carriers. The inf luences of the Pt layer were confirmed by investigating the photocurre nt transient behaviors. In the case of the Pt/WO3/p-Si electrode, part icularly high quantum efficiencies were obtained in a wavelength range of 430-700 nm, possibly due to inelastic electron-electron scattering . The Pt/WO3/p-Si electrodes did not show any detectable corrosion aft er illumination for 5 h according to the observation of surface micros tructures. (C) 1998 American Institute of Physics. [S0021-8979(98)0781 9-0].