Department of Chemistry, University of Perugia, Via Elce di Sotto 8, 06123 Perugia PG, Italy.
J Phys Chem A. 2009 Dec 31;113(52):14375-88. doi: 10.1021/jp903433e.
Density functional calculations for both periodic slabs and different size cluster models of the hydrogen-terminated (100) surface of silicon are used to study a new configuration, formed by a silylene center interacting with vicinal silicon dihydrides through nonconventional hydrogen bonds. A comparison between slab-model and cluster-model approaches to modeling surface silylene defect formation processes is presented. The cluster models are used to analyze the structure and bonding of the silylene with a Lewis acid and base, showing the Zwitterionic nature of the defect. The silylene is also demonstrated to behave as a strong Brønsted acid. The stabilization of the silylene defect via interaction with species unavoidably present in the HF(aq)-etching solution is investigated. Finally, the negative chemical shift observed by X-ray photoelectron spectroscopy in the HF(aq)-etched (100) Si surface is attributed to the occurrence of silylene defect.
采用密度泛函理论对周期性平板和不同尺寸的硅氢终止（100）表面团簇模型进行计算，研究了一种新的构型，该构型由一个硅烯中心通过非传统氢键与临近的硅二氢相互作用形成。提出了一种用平板模型和团簇模型来模拟表面硅烯缺陷形成过程的比较方法。利用团簇模型分析了具有路易斯酸和碱的硅烯的结构和键合，表明了该缺陷的两性离子性质。还证明了硅烯是一种强布朗斯特酸。通过与 HF(aq)-刻蚀溶液中不可避免存在的物质相互作用来稳定硅烯缺陷。最后，X 射线光电子能谱在 HF(aq)-刻蚀（100）Si 表面上观察到的负化学位移归因于硅烯缺陷的存在。
