AVS 53rd International Symposium
    Surface Science Thursday Sessions
       Session SS2+EM-ThM

Paper SS2+EM-ThM7
High Thermal Stability of Cross-Linked Aromatic Self-Assembled Monolayers: New Pathways for Nanopattering by Selective Desorption

Thursday, November 16, 2006, 10:00 am, Room 2004

Session: Self-Assembled Monolayers
Presenter: A. Turchanin, University of Bielefeld, Germany
Authors: A. Turchanin, University of Bielefeld, Germany
M. El-Desawy, University of Bielefeld, Germany
A. Gölzhäuser, University of Bielefeld, Germany
Correspondent: Click to Email
Molecular structures with high thermal stability are very desirable for applications in nanoscience and nanotechnology. We report on the thermal stability of cross-linked aromatic self-assembled monolayers (SAMs) on gold surfaces. Cross-linked monolayers were formed by low-energy electron irradiation of biphenylthiol SAMs. The pristine and the cross-linked monolayers were heated in ultra high vacuum to temperatures from 300 up to 1000K and then analyzed by X-ray photoelectron spectroscopy (XPS). We found that the pristine SAM desorbs at 400K, which is accompanied by a breaking of C-S bonds. Despite of a similar C-S bond cleavage of cross-linked SAMs in the same temperature range, their carbon matrix shows a high thermal stability and remains on the surface up to 1000K. We present a detailed analysis of the temperature transformations in pristine and cross-linked SAMs on the basis of XPS data. Using a stencil mask to locally cross-link the SAMs, it is then shown by scanning electron and atomic force microscopy that after the temperature treatment monomolecular sheets of aromatic molecules, corresponding to irradiated areas in the SAM, persist at the surface. This opens a new pathway for nanopattering by the selective desorption of non-cross-linked regions on a e-beam patterned monolayers and for technological applications of SAM coatings.