Spectroscopic Characterization and Transport Properties of Aromatic Monolayers Covalently Attached to Si(111) Surfaces

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• 作者：Yosuke Harada ; Takanori Koitaya ; Kozo Mukai ; Shinya Yoshimoto ; Jun Yoshinobu
• 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：7497-7505
• 全文大小：504K
• 年卷期：v.117,no.15(April 18, 2013)
• ISSN：1932-7455

文摘

We fabricated self-assembled monolayers (SAMs) composed of aromatic molecules with different anchor groups on Si(111) surfaces by wet chemical reactions. We investigated the bonding structures and transport properties by spectroscopic and electrical measurements, respectively. By using simple aromatic molecules (phenol, styrene, and phenylacetylene) as initial precursors, we successfully fabricated aromatic SAMs covalently bonded to Si(111) surfaces through different anchor structures (Si鈥揙鈥? Si鈥揅H₂鈥揅H₂鈥? and Si鈥揅H鈺怌H鈭?. Transmission infrared spectroscopy clarify that the phenyl rings in the SAMs are oriented almost perpendicular to the Si surfaces. High-resolution X-ray photoelectron spectroscopy reveals that the aromatic molecules attach to the Si surface with the surface coverage of 0.5. The experimental results of these spectroscopies lead to a conclusion that the aromatic SAMs form densely packed monolayers on Si(111). Current density鈥搗oltage measurements of Hg/aromatic SAM鈥揝i(111) sandwiched structures revealed that the 鈥淪i(111)鈥揙鈥揚h鈥?(SAM from phenol) show higher conductivity compared with the long-chain alkyl SAM on Si(111).