Investigation of the Epitaxial Growth of Octamethylene-Tetrathiafulvalene (OMTTF) on Substrates of Different Chemical Reactivity

• Published in: Advanced functional materials 2001-06, Vol.11 (3), p.188-192
• Main Authors: Poppensieker, J., Röthig, C., Fuchs, H.
• Format: Article
• Language: English
• Subjects: Ag substrate; Epitaxial growth; OMTTF; Organic molecular beam deposition (OMBD)
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/1616-3028(200106)11:3<188::AID-ADFM188>3.0.CO;2-5

Monolayers of the organic donor OMTTF (octamethylene‐tetrathiafulvalene) were grown on a Ag(100) substrate and on the iodine c(2×2) superstructure on Ag(100) by organic molecular beam deposition (OMBD) under ultra high vacuum (UHV) conditions. The films were characterized by low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). In the monolayer regime the molecules grow on both substrates in an ordered structure. By comparing the degree of long‐range order and the geometrical structure observed on Ag and on iodine with that of OMTTF‐TCNQ we discuss the interplay between the different interactions and long‐range order in epitaxial growth. How do substrate properties affect superstructures of organic adsorbates? Answering this question was the main aim of the study reported here, in which monolayers of OMTTF (see left‐hand part of Figure) were grown on a Ag(100) substrate and on the iodine c(2×2) superstructure on Ag(100). The Figure (right‐hand part) also shows how four sulfur atoms per molecule produce a single observable protrusion in scanning tunneling microscopy.