AVS 49th International Symposium
    Surface Science Thursday Sessions
       Session SS+EL+OF-ThM

Paper SS+EL+OF-ThM7
Modifying the Semiconductor Interface with Organonitriles

Thursday, November 7, 2002, 10:20 am, Room C-112C

Session: Reactions and Patterning of Organics on Silicon
Presenter: M.A. Filler, Stanford University
Authors: M.A. Filler, Stanford University
C. Mui, Stanford University
C.B. Musgrave, Stanford University
S.F. Bent, Stanford University
Correspondent: Click to Email
Organic functionalization of group-IV semiconductor surfaces has recently garnered considerable attention and applications in the areas of molecular electronics, biological recognition, and reagentless micropatterning have been proposed. If these and other concepts are to become technologically feasible, however, the creation of an ordered and selectively grown layer as well as the ability to successively attach additional organic monolayers will be necessary. Organonitrile compounds were studied as potential candidates for first and subsequent layer surface reactions on Si(100)-2x1 and Ge(100)-2x1. Bonding is investigated experimentally with infrared spectroscopy and theoretically with density functional theory. We find that acetonitrile does not react on the Ge(100)-2x1 surface at room temperature and explain this result with kinetic and thermodynamic arguments. A [4+2] cycloaddition product through the conjugated @pi@ system and a [2+2] C=C cycloaddition product through the alkene are found to be the dominant surface adducts for the multifunctional molecule 2-propenenitrile. While the non-conjugated molecules 3-butenenitrile and 4-pentenenitrile are not expected to form a [4+2] cycloaddition product, both show vibrational modes characteristic of this adduct and we propose the possibility of a surface catalyzed reaction. Pathways directly involving only the nitrile functional group are thermodynamically unfavorable at room temperature on Ge(100)-2x1 and the conversion of the remaining nitrile functionality as well as its use in additional surface reactions will also be presented.