Reaction of alkenes with hydrogen-terminated and photooxidized silicon surfaces. A comparison of thermal and photochemical processes.
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.
Mischki
Trevor K
TK
Steacie Institute for Molecular Sciences, Nation Research Council, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada.
Donkers
Robert L
RL
Eves
Brian J
BJ
Lopinski
Gregory P
GP
Wayner
Danial D M
DD
D000475:Alkenes / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008567:Membranes, Artificial; D010084:Oxidation-Reduction; D010777:Photochemistry; D012825:Silicon / Q000737:chemistry*; D014466:Ultraviolet Rays
D000475:Alkenes; D008567:Membranes, Artificial; D006859:Hydrogen; D012825:Silicon