Analysis of the physical and photoelectrochemical properties of c-Si(p)/a-SiC:H(p) photocathodes for solar water splitting

María Del Carmen Mejia, Luis Francisco Sánchez, Mario Kurniawan, Lara Eggert, Alvaro Tejada, Magali Camargo, Rolf Grieseler, Francisco Rumiche, Isabel Díaz, Andreas Bund, Jorge Andrés Guerra

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2 Scopus citations


The photoelectrochemical (PEC) properties of sputtered aluminum doped hydrogenated amorphous silicon carbide thin films grown on p-type crystalline silicon substrates were investigated in 1 M H2SO4 solution under chopped light illumination. Optical and structural properties of the top absorber layer were systematically assessed after post-deposition isochronical annealing treatments. Samples exhibited a noticeable improvement of the opto-electronic properties after thermal treatments. In addition, an abrupt enhancement of the photocurrent was observed reaching a saturation value of 17 mA cm-2 at -1.75 V vs. Ag/AgCl (3.5 M KCl). In this research we propose that this enhancement effect is associated to a charge transfer kinetic mechanism influenced by surface states and the p-type substrate. The latter most likely due to the space charge region extending beyond the absorber layer reaching the substrate. Current density-potential and electrochemical impedance spectroscopy measurements in dark revealed a reduction of the SiO2 native layer at cathodic potentials higher than -1 V vs. Ag/AgCl (3.5 M KCl), which contributes to the high charge transfer kinetic of the system. We believe that these results will contribute to understand the substrate influence in the PEC performance of top absorber layers in multilayer structures for solar water splitting.

Original languageEnglish
Article number195101
JournalJournal of Physics D: Applied Physics
Issue number19
StatePublished - 13 May 2021


  • amorphous semiconductors
  • energy storage
  • isotype heterojunctions
  • surface states
  • water splitting


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