Abstract
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, ßN, was obtained from measurements as a function of chain length at constant force and bias, yielding ßN = 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.
Original language | English |
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Pages (from-to) | 5-14 |
Number of pages | 10 |
Journal | Nanotechnology |
Volume | 13 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2002 |
Keywords
- Electronics and devices
- Surfaces, interfaces and thin films
- Molecular electronic devices
- Atomic force microscopy (AFM)
- AFM