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 Silicon Surface Chemistry and Molecular Electronics Understanding
surface reactions of highly functionalized molecules, including
hydrocarbons on well defined semiconductor substrates is a substantial
part of our interest. A good portion of our published work concerns
reactions on Si(100)-2x1 surface and encompasses several topics related
to preferential binding, electronic structure, coadsorption, blocking
of selected reactive sites (surface titration), weak adsorption, and
surface modifcation following the initial chemical reaction.
Thin films formed by the adsorption of hydrocarbons are important in the development of electronics because several have been shown to be stable at high temperatures. In the interest of developing new electronic devices, we need to develop an understanding of these modified surfaces. One of the current projects focuses on monolayers formed from the coadsorption of two different molecules. The first molecule applied to the surface occupies a known array of surface sites (i.e, every other dimer of reconstructed Si(100)-2x1 surface, every third dimer, etc.). The second molecule is then dosed onto the surface where it chemisorbs onto the remaining surface sites; the first molecule acts as a placeholder that blocks the chemisorption of the second molecule from selected sites. Ideally, the first molecule should desorb intact from the surface at a lower temperature than the second molecule. Therefore, we should be able to heat the surface to a temperature between the desorption temperatures of the two molecules, causing the placeholder to desorb and leaving an ordered array of the second molecule left on the surface. We have been focusing our research on finding a suitable placeholder molecule for the coadsorbed layer; studied molecules include ethylene, 2,3-dimethyl-2-butene, and triethylenediamine. We have been using nitrobenzene as our stable second molecule, for its behavior on Si(100) has been well-documented by our group and as a prototypical aromatic molecule. Other efforts include 1,3-cycloadditions and condensation processes on H-terminated silicon. |
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Relevant Publications: [1] Bocharov, S.; Dmytrenko, O.; Méndez De Leo, L. P. and Teplyakov, A. V. “Azide Reactions for Controlling Clean Silicon Surface Chemistry: Benzylazide on Si(100)-2x1.” J. Am. Chem. Soc. 2006, 128, 9300-9301. [2] Méndez De Leo, L. P. and Teplyakov, A. V. “Nitro Group as a Means of Attaching Organic Molecules to Silicon: Nitrobenzene on Si(100)-2x1.” J. Phys. Chem. B 2006, 110, 6899-6905. [3] Madachik, M. R.; Teplyakov, A. V. manuscript in preparation [4] Leftwich, T. R. and Teplyakov, A. V. Chemical manipulation of multifunctional hydrocarbons on silicon surfaces. Invited review, accepted to Surf. Sci. Rep. |
Dr. Andrew Teplyakov