Soft X-ray Spectroscopy of a Complex Heterojunction in High-Efficiency Thin-Film Photovoltaics: Intermixing and Zn Speciation at the Zn(O,S)/Cu(In,Ga)Se2 Interface

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• 作者：Michelle Mezher ; Rebekah Garris ; Lorelle M. Mansfield ; Monika Blum ; Dirk Hauschild ; Kimberly Horsley ; Douglas A. Duncan ; Wanli Yang ; Marcus Bär ; Lothar Weinhardt ; Kannan Ramanathan ; Clemens Heske
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：December 7, 2016
• 年：2016
• 卷：8
• 期：48
• 页码：33256-33263
• 全文大小：547K
• ISSN：1944-8252

文摘

The chemical structure of the Zn(O,S)/Cu(In,Ga)Se₂ interface in high-efficiency photovoltaic devices is investigated using X-ray photoelectron and Auger electron spectroscopy, as well as soft X-ray emission spectroscopy. We find that the Ga/(Ga+In) ratio at the absorber surface does not change with the formation of the Zn(O,S)/Cu(In,Ga)Se₂ interface. Furthermore, we find evidence for Zn in multiple bonding environments, including ZnS, ZnO, Zn(OH)₂, and ZnSe. We also observe dehydrogenation of the Zn(O,S) buffer layer after Ar⁺ ion treatment. Similar to high-efficiency CdS/Cu(In,Ga)Se₂ devices, intermixing occurs at the interface, with diffusion of Se into the buffer, and the formation of S—In and/or S—Ga bonds at or close to the interface.