Elucidating the conductivity-type transition mechanism of p-type Cu2O films from electrodeposition

Jun Nan Nian, Chien Cheng Tsai, Pao Chung Lin, Hsisheng Teng

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Narrow bandgap Cu2 O films of p- and n-type conductivities are electrodeposited on conducting glass substrates from aqueous Na2 SO4 solutions. These Cu2 O films exhibit photoelectrochemical responses under visible light illumination. The p- and n-type films have different preferred out-of-plane orientations of [111] and [100], respectively. X-ray absorption fine structure spectroscopic analysis shows that the n-type Cu2 O contains a higher degree of lattice disorder. Ultraviolet photoelectron spectroscopy along with the Mott-Schottky electrochemical impedance analysis determines the energy-level diagrams of both the p- and n-type films. On the basis of the structural features obtained, this paper finds that strong Cu2+ absorption on the unstable surface states resulting from the Cu vacancies of Cu2 O can lead to the formation of an inversion layer and thus conductivity transition from p to n type. As a consequence of this p-n transition mechanism, Cu2 O films containing nanocavities for strong Cu2+ absorption exhibit an n-type conductivity, while intact Cu2 O films are p type. A conductivity-type diagram is constructed to show that a subtle change in the deposition parameters can tune the crystal orientation and conductivity type of Cu2 O films.

Original languageEnglish
Pages (from-to)H567-H573
JournalJournal of the Electrochemical Society
Volume156
Issue number7
DOIs
Publication statusPublished - 2009 Jun 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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