@misc{oai:ir.soken.ac.jp:00000233,
 author = {荒, 正人 and アラ, マサト and ARA, Masato},
 month = {2016-02-17, 2016-02-17},
 note = {Organic monolayers on inorganic semiconductors including silicon via covalent bonds such as silicon-carbon (Si-C) have attracted a growing interest as one of the most promising ways to assemble organic molecules with well-defined interfaces. The characteristics of Si-C system are as follows: (a) the interface is thermally and chemically stable, (b) the electric properties can be controlled by doping electron-donating or -withdrawing impurities, and (c)micro- and nano-fabrication techniques established in the field of semiconductor devices are applicable. Following the general introduction (Chapter I ) in which he described the background and history of the research on molecular assemblies, he discussed molecular structure and stability of organic monolayers anchored to Si(111) covalently (Chapter II ), he demonstrated two dimensional patterning of silicon (Chapter III) and three dimensional molecular assemblies (Chapter IV). He prepared silicon cantilevers covered with organic monolayers through covalent bonds and used them for friction force microscopy and non-contact atomic force microscopy (Chapter V).
　Characterization of Organic Monolayers Anchored Covalently to Silicon (111) Surfaces(Chapter II): Organic monolayers anchored to silicon (111) surfaces were prepared through the reaction between 1-alkene molecules and hydrogen-terminated silicon (H-Si) by thermal treatment. The monolayers prepared were characterized by infrared spectroscopy, sum-frequency generation(SFG) spectroscopy, atomic force microscopy (AFM), and so on. ABM images of the monolayers exhibited flat and etcl-pit free terraces with monoatomic steps, indicating the formation of highly ordered densely packed films. SFG spectroscopy revealed that an alkyl chain in the film consisted of an all-trans head part with a twisted stem. It was found that the films became solid-like with increasing reaction temperature. The films were thermally stable up to 440 K in vacuum but irreversible conformational disorder in the chain was introduced by heating the film above 440 K. The monolayers were also chemically stable. The exchange reaction did not occur at ordinal reaction conditions and the films exhibited high resistivity against 8 % NH<SUB>4</SUB>F.
　Nanopatterning of Organic Monolayers Anchored Covalently to Si (111) with An Atomic Force Microscope (Chapter III): Local oxidation of dodecyl monolayers was performed with a contact-mode AFM by applying positive bias voltage to the surface with respect to a conducting cantilever in air. Following the local oxidation, oxidized areas were selectively removed by etching with NH<SUB>4</SUB>F. The grooves formed by the etching were modified by different alkyl molecules. The grooves, whose depth was controlled, were fabricated by etching with the mixture of NH<SUB>4</SUB>F and H<SUB>2</SUB>O<SUB>2</SUB>. AFM lithography of organic monolayers on silicon was found to be useful for nanofabrication of organic/inorganic interfaces based on the Si-C covalent bond.
　Fluorescence from Dye Molecules Anchored to Silicon Surfaces (ChapterIV): 1 - (3 - propenyl) -2, 2, 5, 5- tetramethyl - 2, 5 - disilazole (protected aminopropene) was synthesized and examined the films growth. Fluorescein - 4 - isothiocyanate (FITC) molecules were then immobilized to monolayers. The fluorescence of monolayers, to which FITC molecules were immobilized, was measured. Fluorescence intensity depended on the dopant concentration of silicon substrates. Charge carriers in silicon substrates were thought to play an important role for the fluorescence quenching. 
　Chemical Force Microscopy Using Silicon Cantilevers Covered with Organic Monolayers Anchored via Silicon-Carbon Covalent Bonds (Chapter V): Cantilevers covered with organic monolayers anchored via Si-C covalent bonds were prepared by an UV induced reaction and used for adhesion force measurement and friction force microscopy. Hydrocarbon (CH) and fluorocarbon(CF) areas, patterned by the method described in Chapter III, were distinguished by adhesion force measurement and friction force microscopy. The adhesion force and friction force on CF-areas were larger than those on CH-areas, especially using CF-cantilevers. Large polarizabilities of CF-molecules comparing to CH-molecules were found to enhance the contrast in adhesion and firiction images. 
　Cantilevers covered with organic monolayers were also used for non-contact atomic force microscopy (NC-AFM) of TiO<SUB>2</SUB> (110)-(lxl) surfaces. Clear images of atomic rows on atomically flat terraces were observed with the dodecy-lcoated cantilevers when the samples were biased around 2.0 V with respect to the cantilevers. The bias voltage for alky-lcoated cantlevers required to give clear images was higher than that for uncoated ones. The cantilevers covered with organic monolayers via covalent bonds are useful for chemical force microscopy with contact and non-contact mode atomic force microscopy in various conditions since the interface between molecules and cantilevers is thermally and chemically stable., application/pdf, 総研大甲第750号},
 title = {Study on Molecular Assemblies Anchored to Silicon Surfaces via Sillicon-Carbon Covalent Bonds},
 year = {}
}