Novel Growth of Naphthalene Overlayer on Cu(111) Studied by STM, LEED, and 2PPE

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• 作者：Takashi Yamada ; Masahiro Shibuta ; Yohei Ami ; Yasuhiro Takano ; Akihiro Nonaka ; Keisuke Miyakubo ; Toshiaki Munakata
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：August 12, 2010
• 年：2010
• 卷：114
• 期：31
• 页码：13334-13339
• 全文大小：371K
• 年卷期：v.114,no.31(August 12, 2010)
• ISSN：1932-7455

文摘

Adsorbed structures of naphthalene on Cu(111) have been studied using low temperature scanning tunneling microscope (LT-STM) and low energy electron diffraction (LEED). Starting from single molecules, three kinds of long-range ordered superstructures, (5√3 × 5√3)R30°, (2√3 × 3)rect-1C₁₀H₈, and are observed depending on the molecular concentrations and the substrate temperatures during molecular adsorption. One of the self-assembled ordered phases with a (5√3 × 5√3) R30° periodicity is chiral in adsorption-induced arrangement though a single naphthalene molecule itself has no inherent chirality. In STM images, isolated single molecules appear as depressions whereas the molecules are seen as protrusions in self-assembled layers. Coverage dependent two-photon photoemission (2PPE) spectra show that the adsorption-induced occupied states is formed at around Cu 3d bands, and this results in the enhanced tunneling of occupied state images in assembled layers.