Masahiko Hara

Alkyl Chain Length Effect on Growth Kinetics of n-Alkanethiol Self-Assembled Monolayers on Gold Studied by X-Ray Photoelectron Spectroscopy

Growth kinetics of self-assembled monolayers (SAMs) of n-alkanethiols on gold substrates was studied by X-ray photoelectron spectroscopy (XPS). We compared adsorption kinetics for three alkanethiol homologues: butanethiol (C4SH), dodecanethiol (C12SH), and octadecanethiol (C18SH). Results of quantitative analysis by XPS suggested that the adsorption rate of short alkyl chain thiols is higher than that of long ones on gold substrates at the initial growth stage, in contrast to previous reports. For C4SH SAM formation, we have also confirmed the occurrence of a replacement effect from contamination to SAM on gold, based on our observation of a decrease in the amount of carbon and an increase in the amount of gold where as determined from XPS spectra.

Scanning Tunneling Microscopy Investigations on Heteroepitaxially Grown Overlayers of Cu-Phthalocyanine on Au(111) Surfaces

With its ultrahigh resolution, the STM provides an outstanding capability for the structural analysis of the molecular orderings occurring on single crystalline substrates.

Fixation of protein molecules for STM measurement

New deposition technique, ‘‘guest‐host anchoring method’’, has been developed for scanning tunneling microscopy (STM) visualization of biological macromolecules with clear discrimination against artifacts. The electroactive protein (cytochrome c3) molecules were embedded in the liquid crystal matrix, and imaged by STM as a function of applied voltage. Those STM images are encouraging for potential application of this new method to the STM imagings of a wide range of uncoated biological macromolecules.