AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuM

Paper SS2-TuM7
Fabricating Self-Assembled Monolayers of Selenolates on Noble Metal Substrates

Tuesday, November 16, 2004, 10:20 am, Room 210C

Session: Self Assembled Monolayers
Presenter: A. Shaporenko, Universität Heidelberg, Germany
Authors: A. Shaporenko, Universität Heidelberg, Germany
A. Ulman, Polytechnic University
A. Terfort, Universität Hamburg, Germany
M. Grunze, Universität Heidelberg, Germany
M. Zharnikov, Universität Heidelberg, Germany
Correspondent: Click to Email
Self-assembled monolayers (SAMs) of selenolates can be considered as an alternative to thiolates for fabricating SAMs on noble metal surfaces. To prove this approach, we applied a standard immersion procedure to prepare SAMs from several aliphatic and aromatic selenide and diselenide compounds on gold and silver substrates. The resulting films were characterized by several complementary experimental techniques including infrared refection-absorption spectroscopy (IRRAS), synchrotron based high-resolution X-ray photoelectron spectroscopy (HRXPS), near edge X-ray absorption fine structure spectroscopy, and contact angle measurements. The results suggest a dissotiative mode of monolayer formation from diselenide compounds on both gold and silver. However, in the case of long chain alkylselenides and dialkylselenides, no high quality films were formed. In the case of short chain alkylselenides, semifluorinated alkylselenides, and biphenylselenides, well-defined and densely packed SAMs were fabricated. Only one selenium species, namely selenolate was found in all above-mentioned films on the basis of the Se3d HRXPS spectra. Distinct C1s photoemission peaks were observed and related to well-defined aliphatic or aromatic chain. Characteristic IR absorption bands and X-ray absorption resonances corresponding to intact molecular chains of definite conformation were observed. The information on molecular orientation and packing density was derived.