AVS 49th International Symposium
    Surface Science Friday Sessions
       Session SS-FrM

Paper SS-FrM8
Nanomolecular Motion Induced by Molecular Rectificator in the Self-Assembled Monolayers

Friday, November 8, 2002, 10:40 am, Room C-110

Session: Self-Assembly at Surfaces
Presenter: T. Ishida, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Authors: T. Ishida, National Institute of Advanced Industrial Science and Technology (AIST), Japan
H. Fukushima, JRCHMM -JCII and TPRC, SEIKO EPSON Corporation, Japan
T. Tamaki, National Institute of Advanced Industrial Science and Technology (AIST), Japan
H. Tokumoto, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Correspondent: Click to Email
Nanoscale molecular motion induced by polarity change of the electric field was observed by scanning tunneling microscopy (STM), when small amounts of asymmetrical disulfides containing terphenyl moieties were embedded into pre-assembled dodecanethiol self-assembled monolayers (SAMs). The class of disulfide was specifically designed to perform the large dielectric anisotropy in the terphenyl moiety. At the positive tip bias, few of protrusions were observed. When the STM tip bias turned to negative, many protrusions appeared on the binary monolayer surface. Scanning tunneling spectroscopy (STS) revealed the higher rectification property at the area of the terphenyl terminated monolayer where also showed the higher electrical conduction at the negative tip bias compared to positive one. The higher electrical conduction at the negative tip bias was likely to retract the STM tip, showing the apparent nanomolecular motion by the polarity change. Our observed nanomotion (about 1 min) is much faster than previously observed switching time (at least 20 min).@footnote 1@ Also, the apparent molecular motion can be observed in the case of nanometer scale domains as well as single molecule. @FootnoteText@ @footnote 1@Z.J. Donhauser et al., Science 292 (2001) 2303-2307.