TY - JOUR
T1 - Electrical, Photoelectrochemical, and Photoelectron Spectroscopic Investigation of the Interfacial Transport and Energetics of Amorphous TiO2/Si Heterojunctions
AU - Hu, Shu
AU - Richter, Matthias H.
AU - Lichterman, Michael F.
AU - Beardslee, Joseph
AU - Mayer, Thomas
AU - Brunschwig, Bruce S.
AU - Lewis, Nathan S.
N1 - Funding Information:
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. Kimberly Papadantonakis for assistance with editing this manuscript.
Publisher Copyright:
© 2015 American Chemical Society.
PY - 2016/2/18
Y1 - 2016/2/18
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jpcc.5b09121
DO - 10.1021/acs.jpcc.5b09121
M3 - Article
AN - SCOPUS:84959036580
VL - 120
SP - 3117
EP - 3129
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 6
ER -