Electrical, Photoelectrochemical, and Photoelectron Spectroscopic Investigation of the Interfacial Transport and Energetics of Amorphous TiO2/Si Heterojunctions

Shu Hu, Matthias H. Richter, Michael F. Lichterman, Joseph Beardslee, Thomas Mayer, Bruce S. Brunschwig, Nathan S Lewis

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Solid-state electrical, photoelectrochemical, and photoelectron spectroscopic techniques have been used to characterize the behavior and electronic structure of interfaces between n-Si, n+-Si, or p+-Si surfaces and amorphous coatings of TiO2 formed using atomic-layer deposition. Photoelectrochemical measurements of n-Si/TiO2/Ni interfaces in contact with a series of one-electron, electrochemically reversible redox systems indicated that the n-Si/TiO2/Ni structure acted as a buried junction whose photovoltage was independent of the formal potential of the contacting electrolyte. Solid-state current-voltage analysis indicated that the built-in voltage of the n-Si/TiO2 heterojunction was 0.7 V, with an effective Richardson constant 1/100th of the value of typical Si/metal Schottky barriers. X-ray photoelectron spectroscopic data allowed formulation of energy band-diagrams for the n-Si/TiO2, n+-Si/TiO2, and p+-Si/TiO2 interfaces. The XPS data were consistent with the rectifying behavior observed for amorphous TiO2 interfaces with n-Si and n+-Si surfaces and with an ohmic contact at the interface between amorphous TiO2 and p+-Si.

Original languageEnglish
Pages (from-to)3117-3129
Number of pages13
JournalJournal of Physical Chemistry C
Issue number6
Publication statusPublished - Feb 18 2016


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

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