Mechanical and charge transport properties of alkanethiol self-assembled monolayers on a au(111) surface: the role of molecular tilt.
Langmuir
; 24(5): 2219-23, 2008 Mar 04.
Article
em En
| MEDLINE
| ID: mdl-18225934
ABSTRACT
The relationship between charge transport and mechanical properties of alkanethiol self-assembled monolayers (SAMs) on Au(111) films has been investigated using an atomic force microscope with a conductive tip. Molecular tilts induced by the pressure applied by the tip cause stepwise increases in film conductivity. A decay constant beta = 0.57 +/- 0.03 A-1 was found for the current passing through the film as a function of tip-substrate separation due to this molecular tilt. This is significantly smaller than the value of approximately 1 A-1 found when the separation is varied by changing the length of the alkanethiol molecules. Calculations indicate that, for isolated dithiol molecules S-bonded to hollow sites, the junction conductance does not vary significantly as a function of molecular tilt. The impact of S-Au bonding on SAM conductance is discussed.
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MEDLINE
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En
Ano de publicação:
2008
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Article