AVS 55th International Symposium & Exhibition
    Surface Science Wednesday Sessions
       Session SS2+NC-WeM

Paper SS2+NC-WeM10
Adsorption of the Thiol Molecule (SCH3)2 on a Metallic Quantum Well System

Wednesday, October 22, 2008, 11:00 am, Room 209

Session: Functional Metal Oxides and Quantum Metal Structures
Presenter: L. Tskipuri, Rutgers University
Authors: L. Tskipuri, Rutgers University
R.A. Bartynski, Rutgers University
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We have studied the bonding of the thiol molecule dimethyldisulfide (SCH3)2 on ultrathin Cu and Co films that exhibit metallic quantum well (MQW) states using inverse photoemission (IPE), reflection-absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD). This thiol is similar to more complex organic molecule that exhibits the self-assembled properties on metal surfaces. After a room temperature exposure of the Cu surface to the thiol molecule at a dose of ~ 2.5 L, a c(2 x 2) low energy electron diffraction (LEED) pattern confirmed that the adsorbate forms an ordered overlayer. A large sulfur signal is observed in Auger electron spectroscopy (AES) and the C-H stretch mode was observed in IR with a frequency of 2915 cm-1 confirming molecular adsorption. Changes in the IPE spectrum upon adsorption are dominated by suppression of the substrate-related features, although some weak adsorbate-induced peaks are also observed. Both experimental and theoretical evidence indicates that electronic orbitals involved in molecule-surface bonding are in the same energy range as the MQW states of the substrate and the possible influence of MQW states on molecular adsorption and self-assembly of the thiol molecule will be discussed.