title: Reaction of alkenes with hydrogen-terminated and photooxidized silicon surfaces. A comparison of thermal and photochemical processes.
abstract: Reagentless micropatterning of hydrogen-terminated Si(111) via UV irradiation through a photomask has proven to be a convenient strategy for the preparation of ordered bicomponent monolayers. The success of this technique relies upon the differential rate of reaction of an alkene with the hydrogen-terminated and photooxidized regions of the surface. Monolayer formation can be accomplished under either thermal or photochemical conditions. It was observed that, after 3 h, reaction in neat alkene solution irradiation (Rayonet, 300 nm) afforded the expected patterned surface, while thermal conditions (150 degrees C) resulted in a partial loss of pattern fidelity. Monolayer properties and formation were studied on oxidized and hydrogen-terminated silicon under thermal and photochemical initiation, by contact angle, ellipsometry, Fourier transform infrared spectroscopy, high-resolution electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. Results show that alkenes add to silanol groups on the silica surface in a manner consistent with acid catalysis: once attached to the surface, the silica oxidized the hydrocarbon.
authors.affiliation: Steacie Institute for Molecular Sciences, Nation Research Council, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Trevor K
authors.initials: TK
authors.lastname: Mischki
authors.forename: Robert L
authors.initials: RL
authors.lastname: Donkers
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Eves
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Lopinski
authors.forename: Danial D M
authors.initials: DD
authors.lastname: Wayner
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008567:Membranes, Artificial; D010084:Oxidation-Reduction; D010777:Photochemistry; D012825:Silicon / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000475:Alkenes; D008567:Membranes, Artificial; D006859:Hydrogen; D012825:Silicon