On the increase of the photocurrent quantum efficiency of GaP photoanodes due to (photo)anodic pretreatments

D. Vanmaekelbergh*, B. H. Erné, C. W. Cheung, R. W. Tjerkstra

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

It has been found that the photocurrent quantum efficiency of n-type GaP single crystal electrodes illuminated with visible light (green-blue) increases markedly as a consequence of photoanodic etching or polarization at very positive potentials. The origins of this increase have been systematically investigated. Two effects are of importance. Photoanodic etching leads to a roughening of the surface; as a consequence the incident light is scattered and absorbed more effectively in the region of the solid in which electron-hole pairs are separated by diffusion or migration. In addition, photoanodic current flow or severe positive polarization lead to a considerable increase of the diffusion length of the photogenerated holes. This effect is attributed to passivation of hydrogen-related recombination centers by hole capture and subsequent release of hydrogen.

Original languageEnglish
Pages (from-to)689-698
Number of pages10
JournalElectrochimica Acta
Volume40
Issue number6
DOIs
Publication statusPublished - Apr 1995

Keywords

  • bulk recombination
  • gallium phosphide
  • morphology
  • photoanodic etching
  • photoelectrochemistry

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