Liquid-Phase Adsorption of Sulfur on Germanium: Reaction Mechanism and Atomic Geometry

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• 作者：Claudia Fleischmann ; Michel Houssa ; Matthias M眉ller ; Burkhard Beckhoff ; Hans-Gerd Boyen ; Marc Meuris ; Kristiaan Temst ; Andr茅 Vantomme
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：April 18, 2013
• 年：2013
• 卷：117
• 期：15
• 页码：7451-7458
• 全文大小：412K
• 年卷期：v.117,no.15(April 18, 2013)
• ISSN：1932-7455

文摘

We present a fundamental study of the monolayer adsorption of sulfur on Ge(100) surfaces from aqueous (NH₄)₂S solution. This treatment shows promising perspectives for the passivation of high-mobility semiconductor surfaces and is therefore presently of great technological importance. The adsorption mechanisms as well as the adsorption geometry are thoroughly investigated at the atomic scale, by both experiment and theory, applying X-ray absorption spectroscopy and molecular dynamics simulations. Our findings indicate that sulfidation in solution results in the formation of Ge鈥揝鈥揋e bridges along the [110] direction, with no indication for 鈭扴H surface groups. A S鈥揋e bond length of 2.25 卤 0.05 脜 was deduced, which is affected by the chemical environment of the sulfur atoms, i.e., by residual surface oxides. Our study provides novel insights into the surface termination and atomic structure of (NH₄)₂S-treated Ge(100) surfaces and discusses possible differences from in situ sulfur adsorption methods such as H₂S or S₂ exposure.