AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP13
Isocyanate and Isothiocyanate Reactions at the Ge(100)-2x1 Surface

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: P.W. Loscutoff, Stanford University
Authors: P.W. Loscutoff, Stanford University
S.F. Bent, Stanford University
Correspondent: Click to Email
Recently, multiple layer deposition of organic molecules was demonstrated using the highly reactive isocyanate moiety. Continuing this work, we have studied the reactions of several isocyanates and isothiocyanates on the Ge(100)-2x1 surface using multiple internal reflection Fourier transform infrared spectroscopy. Results for phenyl isocyanate indicate that the molecule adsorbs as a [2+2] reaction product between the C=N of the isocyanate group and the Ge surface dimer, in agreement with the published reaction product for 1,4-phenylene diisocyanate. Adsorption studies of mono-isothiocyanates suggest the presence of a sulfur dative-bonded state as well as a cycloaddition product between the isothiocyanate group and the Ge dimer. The adsorption product for 1,4-phenylene diisothiocyanate also differs from that of the isocyanate analog, 1,4-phenylene diisocyanate, and appears to be adsorbing as a [3+2] reaction product. Nonetheless, the spectra show that there is an intact isothiocyanate moiety present in the adsorbed product, indicating the potential for a multiple layer reaction scheme. Future work includes reacting this intact isothiocyanate moiety with ethylene diamine to construct ultra thin films by molecular layer deposition, as well as utilizing X-ray photoelectron spectroscopy to further characterize the nature of isothiocyanate bonding at the Ge(100)-2x1 surface.