Few-Layer Silicon Films on the Ag(111) Surface

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• 作者：Han-De Chen ; Ko-Hsiang Chien ; Cho-Ying Lin ; Tai-Chang Chiang ; Deng-Sung Lin
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 11, 2016
• 年：2016
• 卷：120
• 期：5
• 页码：2698-2702
• 全文大小：389K
• ISSN：1932-7455

文摘

Growth by molecular beam epitaxy (MBE) of Si on Ag(111) results in a two-dimensional film with (√3 × √3) surface structure at near monolayer (ML) coverage. The same (√3 × √3) pattern persists for coverages of Si up to several MLs. The atomic structure of the resulting Si film has posed an intriguing question. One possible scenario is that Ag acts as a surfactant to foster the low-temperature growth of metastable silicene multilayers, which would be an analogue of graphite and a new state of Si. Yet another possibility is the formation of diamond-structured Si. In our experiment, we use low-temperature scanning tunneling microscopy (LT-STM) to observe the chemical response of the film surface exposed to an atomic deuterium (D) beam. We find D displaces the Ag surfactant adatoms, resulting in a D-terminated (1 × 1) surface. The displaced Ag atoms migrate on the surface to form Ag(111) crystallites. The same reactions have been observed for a Si(111) bulk single-crystal surface decorated by Ag. The results confirm that the surfaces of the few-layer Si films grown on Ag(111) are Ag terminated and indirectly suggest that the films have a diamond-like structure.