Once again we want to congratulate our latest alumni:
- Lukas Hergt: Epitaktisches Wachstum kristalliner
Acenfilme auf Alkalihalogenidoberflächen (Bachelor's
- Johannes Völkner: Investigation of the Thermal Stability and Structure of Stilbenedithiol on Gold (Master's Thesis)
- Tobias Breuer: Preparation and
Characterization of thin films of organic semiconductors and their
heterostructures (PhD Thesis)
- Alexander Mänz: Herstellung und Charakterisierung epitaktischer TTF-TCNQ-Dünnfilme auf Kaliumchlorid-Substraten (Master´s Thesis)
- Andrea Karthäuser: Reibungskraftuntersuchungen Mikrokontakt-gestempelter selbst-assemblierender Monolagen (Bachelor´s Thesis)
- Leonard von Helden: Untersuchung der Temperaturabhängigkeit des Sticking-Koeffizienten von Pentacene mittels Schwingquarzwaage (Bachelor´s Thesis)
Since the end of decembre 2010 the offices of our group are no longer in Renthof 5, but in Renthof 7, 2nd floor. Detailed information about room numbers of single members is presented in "Members".
Within the Hot Topic regularly latest research issues and publications are presented.
Temporal Evolution of Benzenethiolate-SAMs on Cu(100) (Christian Schmidt, Jan Götzen, Gregor Witte)
Former Hot Topics:
The structure and thermal stability of self-assembled monolayers (SAMs) of benzenethiolate (BT) on Cu(100) have been studied by means of thermal desorption spectroscopy (TDS), scanning tunneling microscopy (STM), low energy electron diffraction (LEED), UV photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and near-edge X-ray adsorption fine structure spectroscopy (NEXAFS). Vapor deposition at room temperature yields a well ordered and densely packed c(6 x 2) saturation structure. At room temperature this film is, however, metastable and transforms via partial decomposition by cleavage of the S-C bond into a less densely packed layer which reveals a coexisting p(2x2) phase. Such a transition occurs on a time scale of several days and is accompanied by a reduction of the work function change with respect to the bare Cu(100) surface from Φ = -0.9eV for a freshly prepared saturated layer to -0.5eV for an aged film. TDS experiments exhibit the presence of two distinct desorption channels (dissociative and intact desorption) occurring at different temperatures which reflects a variation of the local Cu-S interaction strength of BT at differently coordinated adsorption sites. Heating above room temperature causes rapid degradation and continuous thinning of BT films while above 500K all thiolate species have desorbed or dissociated leaving a sulfide overlayer behind which is accompanied by a substrate reconstruction. Interestingly, the upright orientation of BT adopted in the saturated monolayer remains almost identical upon heating and demonstrates the absence of a downward tilting upon thermal induced thinning of the film.
Link to Publication (sufficient access rights neccessary)