AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP24
Chemistry of Bifunctional Nitro Group-containing Molecules on Silicon: a Cryogenic Approach to Selective Self-assembly in Vacuum

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: S. Bocharov, University of Delaware
Authors: S. Bocharov, University of Delaware
A.V. Teplyakov, University of Delaware
Correspondent: Click to Email
Surface chemistry of alkyl and aryl compounds containing nitro-group on Si(100)-2x1 has been investigated using multiple internal reflection Fourier-transform infrared spectroscopy, Auger electron spectroscopy, and temperature-programmed desorption/reaction mass spectrometry. Despite theoretical prediction for essentially barrierless interaction of nitromethane with this silicon surface, all the nitroderivatives studied physisorb molecularly within a monolayer coverage on Si(100)-2x1 at 95 K. Surface chemical reaction involving nitro-group occurs around 140 K regardless of the nature of the alkyl/aryl substituent studied. Thus, a significant energy barrier, approximately 8 kcal/mol, is established for the interaction of these molecules with the Si(100)-2x1 surface. An opportunity of selective self-assembly using the advantage of cryogenic conditions to control the kinetics of surface reactions will be discussed. Further surface annealing studies suggest that all nitrogen and oxygen atoms remain on a surface even at the temperatures as high as 900 K, while some carbon is removed as a corresponding hydrocarbon molecule.