AVS 50th International Symposium
    Nanometer Structures Tuesday Sessions
       Session NS-TuP

Paper NS-TuP25
Exploration of Chemical Bonding Forms for Producing Organic Monolayers Directly Attached to Silicon

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: N. Maeda, Nagoya University, Japan
Authors: N. Maeda, Nagoya University, Japan
N. Saito, Nagoya University, Japan
H. Sugimura, Nagoya University, Japan
O. Takai, Nagoya University, Japan
Correspondent: Click to Email
Self-assembled monolayer (SAM) formed through the chemical reaction between 1-alkene and hydrogen-terminated silicon (Si-H) is an attractive material for molecular electronic devices, since such a monolayer is directly attached to Si without inserting an oxide layer. This is advantageous for electronic applications of the SAMs and is distinct from an organosilane SAM on Si which needs the oxide interlayer. Furthermore, such a directly- bonded SAM is chemically durable to HF solution more than the organosilane SAM.@footnote 1@ However, an understanding of chemical reactivities of Si-H surfaces to organic molecules is still in an insufficient level. Here we report on SAM formation on Si-H from various precursor organic molecules including 1-hexadecen, phenylacetylene, 1-undecanol, 4-bromomethylbiphenyl, p-phenylenediamine, terephthaldialdehyde,etc. Si-H samples were prepared through the etching of Si(111) substrates in 5%-HF. A Si-H sample was then refluxed at a temperature ranging from 100 to 180 °C for several hours in a precursor liquid or a organic solution of a precursor under an atmosphere purged with N@sub 2@. The treated sample was examined with a water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy in order to confirm SAM formation. In the case of 1- hexadecen, phenylacetylene, 1-undecanol, there were no oxidized Si peaks in XPS. This indicates that densely packed monolayers were formed so that the Si substrates were protected form oxidation. However, in the case of the other precursors, the Si substrates oxidized showing that such monolayers were less densely packed. @FootnoteText@ @footnote 1@N. Saito, S. Youda, K. Hayashi, H. Sugimura and O. Takai, Chem. Lett. 31, 1194 (2002).