STM study of stilbene self-organized on the Ag/Ge(111) surface
C.-S. Tsai, C. Su, J.-K. Wang, and J.-C. Lin
Langmuir 19, 822 (2003)

    The interfacial structures of trans-stilbene (TSB) on Ag/Ge(111)-()R30° were studied by a low-temperature scanning tunneling microscopy (LT-STM) in ultra-high vacuum (UHV). Stilbene overlayers were prepared by vapor deposition at a substrate temperature of 200 K and imaged after cooling the samples to 100 K. High-resolution images allow the identification of individual molecules, with TSB appearing with a distinctive oblong shape. From in-situ observation of the substrate lattice, the TSB monolayers were found to form a (2x1) structure.  Due to the excellent matching of unit cell length for Ag/Ge(111)-()R30° to the molecular length of TSB, the interaction between TSB and the substrate surface plays the controlling role in influencing the structure of the TSB overlayers. A model for the unit cell of TSB-monolayers is proposed and discussed.