Redox-active organic monolayers deposited on silicon surfaces for the fabrication of molecular scale devices
by N. Bellec, A. Faucheux, F. Hauquier, D. Lorcy, B. Fabre
International Journal of Nanotechnology (IJNT), Vol. 5, No. 6/7/8, 2008

Abstract: Different Si(111) surfaces covalently derivatised with alkyl monolayers terminated by redox-active centres, namely reversibly oxidisable ferrocene and tetrathiafulvalene (TTF), and electrochemically polymerisable pyrrole, have been prepared. Ferrocene and pyrrole were attached to the silicon surface using carbodiimide coupling between an amino-substituted derivative and a pre-assembled acid-terminated monolayer. TTF monolayers were produced from the direct reaction of an alcohol-substituted TTF derivative with hydrogen-terminated Si(111). The electrochemical oxidation of the pyrrole-modified surface in the presence of pyrrole yielded strongly adherent and smooth conducting polypyrrole films, the thickness of which could be easily controlled from the consumed electrical charge. The hybrid polypyrrole/pyrrole monolayer/Si(111) junction showed the expected metal-insulator-semiconductor (MIS) diode behaviour with a rectification factor at ±2 V of ca. 280. The electrochemical characteristics of the ferrocene- and TTF-modified surfaces evidenced a single and two one-electron system(s) respectively, located at potentials very close to those observed with the electroactive compounds in solution. The surface coverages of ferrocene and TTF were 0.23 and 0.15 per surface silicon atom respectively. Moreover, the rate constants of electron transfer were found to be 50 s⁻¹ and 25 s⁻¹ for the ferrocene and TTF monolayers respectively.

Online publication date: Sat, 14-Jun-2008

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

 
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Nanotechnology (IJNT):
Login with your Inderscience username and password:

Username:        Password:          Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email subs@inderscience.com