M. Furuhashi, J. Yoshinobu
May 6, 2010
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Influential Citations
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Journal
Journal of Physical Chemistry Letters
Abstract
We investigated the chemical state and molecular orientation of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) adsorbed on a hydrogen-terminated Si(111) (1 × 1) surface using transmission infrared (IR) spectroscopy. We deposited F4-TCNQ molecules on H−Si(111) by a wet chemical method. Similar to evaporated F4-TCNQ molecules on various substrates in vacuum, we observed anionized F4-TCNQ on the H−Si(111) substrate. The incident angle dependence of the IR spectra reveals that this F4-TCNQ anion lies flatly on the surface. On the other hand, minority neutral F4-TCNQ species assume random orientation, judging from the comparison between s- and p-polarized IR spectra. We conclude that the first layer on the H−Si surface is a flat-lying anion species and the upper layers consist of randomly oriented neutral molecules.