title: Hidden electrochemistry in the thermal grafting of silicon surfaces from grignard reagents.
abstract: Covalent grafting of alkyl chains on silicon can be obtained by thermal treatment in Grignard reagents. Alkyl halide present in the Grignard solution as an impurity appears to play a key role in the grafting process. Grafting efficiency is improved when the alkyl halide concentration is increased. It is also enhanced on n-type substrates as compared to p-type substrates and when alkyl bromides are present in solution rather than alkyl chlorides. The grafting reaction involves a zero-current electrochemical step. A reaction model in which simultaneous Grignard oxidation and alkyl halide reduction take place at the silicon surface accounts for all these observations. Alkyl halide reduction is the rate-determining step. Negative charging of the silicon surface lowers the energetic barrier for this reaction, allowing for efficient grafting on n-Si.
authors.affiliation: Laboratoire de Physique de la Matière Condensée, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Samira
authors.initials: S
authors.lastname: Fellah
authors.forename: Rabah
authors.initials: R
authors.lastname: Boukherroub
authors.forename: François
authors.initials: F
authors.lastname: Ozanam
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Chazalviel