Hydrogen evolution on platinum-coated p-silicon photocathodes

The influence of various surface morphologies of Pt-coated p-Si electrodes on the photoelectrochemical formation of hydrogen was investigated. To improve the electrocatalytic activity and the stability of monocrystalline p-type silicon electrodes different Pt films have been prepared by various deposition processes. The morphology, atomic concentration, and chemical binding states were analysed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The surface structures of Pt-coated p-Si photocathodes, e.g. ultrathin Pt films or submonolayers prepared by physical vapour deposition (PVD) techniques or Pt island topographies formed by electrochemical processes, lead to specific photocurrent-voltage characteristics indicating that these surface structures can produce hydrogen with a high conversion efficiency. Since homogeneous Pt surface layers on p-Si yield ohmic contacts or low Schottky barrier heights more efficient structures are formed by Pt island topographies. Copyright (C) 1996 International Association for Hydrogen Energy