Electrical, Photoelectrochemical, and Photoelectron Spectroscopic Investigation of the Interfacial Transport and Energetics of Amorphous TiO₂/Si Heterojunctions
Abstract
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.
Additional Information
© 2015 American Chemical Society. Received: September 18, 2015. Revised: December 7, 2015. Publication Date (Web): December 15, 2015. This work was supported through the Office of Science of the U.S. Department of Energy under Award DE-SC0004993 to the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub. The authors thank Dr. Gang Liu and Prof. Chongwu Zhou at the University of Southern California for their support of variable-temperature solid-state transport measurements. The authors also acknowledge Dr. Slobodan Mitrovic and Natalie Becerra for assistance in the collection of XPS data, as well as Dr. Kimberley Papadantonakis for assistance with editing this manuscript. S.H. and M.H.R. contributed equally to this work. The authors declare no competing financial interest.Attached Files
Supplemental Material - jp5b09121_si_001.pdf
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Additional details
- Eprint ID
- 64156
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- CaltechAUTHORS:20160202-092151875
- Department of Energy (DOE)
- DE-SC0004993
- Joint Center for Artificial Photosynthesis (JCAP)
- Created
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2016-02-02Created from EPrint's datestamp field
- Updated
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2023-03-30Created from EPrint's last_modified field
- Caltech groups
- JCAP