Making electrical contacts to molecular monolayers

Autor: Ana L. Moore, Devens Gust, Alex Primak, Thomas A. Moore, Stuart Lindsay, Otto F. Sankey, Xristo Zarate, Xiaodong Cui, John K. Tomfohr, G. Harris
Rok vydání: 2001
Předmět:
Zdroj: ResearcherID
ISSN: 1361-6528
0957-4484
DOI: 10.1088/0957-4484/13/1/302
Popis: Electrical contacts between a metal probe and molecular monolayers have been characterized using conducting atomic force microscopy in an inert environment and in a voltage range that yields reversible current-voltage data. The current through alkanethiol monolayers depends on the contact force in a way that is accounted for by the change of chain-to-chain tunnelling with film thickness. The electronic decay constant, βN, was obtained from measurements as a function of chain length at constant force and bias, yielding βN = 0.8±0.2 per methylene over a ±3 V range. Current-voltage curves are difficult to reconcile with this almost constant value. Very different results are obtained when a gold tip contacts a 1,8-octanedithiol film. Notably, the current-voltage curves are often independent of contact force. Thus the contact may play a critical role both in the nature of charge transport and the shape of the current-voltage curve.
Databáze: OpenAIRE