Competing Pathways in N-Allylurea Adsorption on Si(111)-(7 脳 7)

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• 作者：Valentina De Renzi ; Ga毛lle F. Arnaud ; Umberto del Pennino
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：March 8, 2012
• 年：2012
• 卷：116
• 期：9
• 页码：5673-5680
• 全文大小：336K
• 年卷期：v.116,no.9(March 8, 2012)
• ISSN：1932-7455

文摘

Functionalization of silicon surfaces with N-allylurea (CH₂鈺怌H鈥揅NH鈥揅O鈥揘H₂) represents a valuable strategy to obtain covalently bonded Si鈥揅 interfaces with amino and/or carbonyl termination. In this work, we studied N-allylurea adsorption on the Si(111)-(7 脳 7) surface by combining X-ray and ultraviolet photoemission spectroscopy (XPS and UPS) with high resolution energy loss spectroscopy (HREELS) measurements. XPS core level analysis provides information on the molecular attachment process. Si鈥揅 covalent bonding is evidenced by the presence of a C 1s component at 284.8 eV, while interaction through N鈥揝i bonding is proved by the presence of a N 1s component at 397.8 eV. Three different adsorption mechanisms are envisaged: (I) [2 + 2]-like cycloaddition occurring at the rest atom鈥揳datom dimer through cleavage of the vinyl group, (II) Si鈥揘 bonding at adatom sites upon cleavage of NH₂ and rearrangement of the ureic group to form an imidol species (鈭扤鈺怌鈥揙H), with release of a H atom, and (III) hydrosilylation at adatom sites, through cleavage of the vinyl group and involvement of H atoms provided by reaction II.