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

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• 作者：Shu Hu ; Matthias H. Richter ; Michael F. Lichterman ; Joseph Beardslee ; Thomas Mayer ; Bruce S. Brunschwig ; Nathan S. Lewis
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 18, 2016
• 年：2016
• 卷：120
• 期：6
• 页码：3117-3129
• 全文大小：579K
• ISSN：1932-7455

文摘

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.