Adsorption and self-assembled structures of sexithiophene on the Si(111)-√3×√3-Ag surface

Takashi Yokoyama; Mitsunori Kawasaki; Tomotaka Asari; Shinya Ohno; Masatoshi Tanaka; Yoshihide Yoshimoto

doi:10.1063/1.4921568

Adsorption and self-assembled structures of sexithiophene on the Si(111)-√3×√3-Ag surface

J Chem Phys. 2015 May 28;142(20):204701. doi: 10.1063/1.4921568.

Authors

Takashi Yokoyama¹, Mitsunori Kawasaki¹, Tomotaka Asari², Shinya Ohno², Masatoshi Tanaka², Yoshihide Yoshimoto³

Affiliations

¹ Department of Nanoscience and Technology, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
² Department of Physics, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
³ Department of Applied Mathematics and Physics, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan.

PMID: 26026455
DOI: 10.1063/1.4921568

Abstract

The adsorption and self-assembled structures of α-sexithiophene (α-6T) have been investigated on a Si(111)-Ag surface using scanning tunneling microscopy (STM), low-energy electron diffraction, and density functional theory calculations. The adsorbed α-6T molecules are arranged into unidirectional molecular rows with a side-by-side orientation. The molecular rows reveal three kinds of appearances in the filled-state STM images, which reflect the distinct adsorption sites. From tunneling spectroscopy, we find that the filled-state STM images of α-6T should be influenced by the surface states of Si(111)-Ag. At one monolayer coverage, sequentially ordering of the triple molecular rows results in the close-packed arrangement of the α-6T overlayer.