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Keywords:

  • heterojunctions;
  • Ohmic contact;
  • photocatalysis;
  • Schottky contact;
  • semiconductors

Abstract

The relationship between the contact type in metal–semiconductor junctions and their photocatalytic efficiencies is investigated. Two metal–semiconductor junctions, silver on zinc oxide (Ag/ZnO) and platinum on zinc oxide (Pt/ZnO) serve as model system for Ohmic and Schottky metal–semiconductor contact, respectively. Ag/ZnO, with Ohmic contact, exhibits a higher photocatalytic efficiency than Pt/ZnO, with Schottky contact. The direction of electric fields within the semiconductor is found to play a crucial role in the separation of photogenerated charges, and thus strongly influences the photocatalytic efficiency.