AVS 47th International Symposium
    Organic Films and Devices Wednesday Sessions
       Session OF-WeA

Paper OF-WeA6
Friction Force Microscopy Study on Photodegradation of Organosilane Self-assembled Monolayers Irradiated with a Vacuum Ultraviolet Light at 172 nm

Wednesday, October 4, 2000, 3:40 pm, Room 313

Session: Self-Assembled Monolayers: Electron Transfer and Film Properties
Presenter: H. Sugimura, Nagoya University, Japan
Authors: H. Sugimura, Nagoya University, Japan
K. Hayashi, Nagoya University, Japan
O. Takai, Nagoya University, Japan
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Photodegradation of organosilane self-assembled monolayers (SAMs), under the presence of atmospheric oxygen molecules, has been studied using an excimer lamp radiating vacuum ultra-violet (VUV) light of 172 nm in wavelength. A SAM was prepared on each of Si substrates covered with native oxide from a precursor of octadecyltrimethoxysilane by a chemical vapor deposition method.@footnote 1@ The SAM-covered samples were photoirradiated under a controlled pressure from 10 to 10@super 5@ Pa. As confirmed by water contact angle measurements, infrared reflection-absorption spectroscopy and X-ray photoelectron spectroscopy, the SAM was decomposed and removed due to the VUV-irradiation. This photodegradation mechanism is ascribed to dissociative excitation of C-C and C-H bondings in the organosilane molecules and to subsequently proceeded oxidation with atomic oxygen radicals generated simultaneously by the VUV-irradiation of O@sub 2@ molecules. Furthermore, micropatterning of the SAM was demonstrated by a simple photomask-contacting method.@footnote 2@ Due to a distinct difference in frictional force in contact-mode atomic force microscopy between the VUV-irradiated and unirradiated regions, the photoprinted pattern was clearly imaged. The VUV-irradiated region showed stronger frictional force than the unirradiated SAM surface. Patterning conditions were optimized based on these results obtained by frictional force microscopy. A micropattern of 2 µm in width was successfully photoprinted on the SAM. @FootnoteText@ @footnote 1@A. Hozumi et al. Langmuir,15 (1999) 7600. @footnote 2@H. Sugimura et al. Langmuir,16 (2000) 885.