Molecular length, monolayer density, and charge transport: Lessons from Al-AlOx/alkyl-phosphonate/Hg junctions

Igal Levine, Stephanie M. Weber, Yishay Feldman, Tatyana Bendikov, Hagai Cohen, David Cahen, Ayelet Vilan

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

A combined electronic transport-structure characterization of self-assembled monolayers (MLs) of alkyl-phosphonate (AP) chains on Al-AlOx substrates indicates a strong molecular structural effect on charge transport. On the basis of X-ray reflectivity, XPS, and FTIR data, we conclude that "long" APs (C14 and C16) form much denser MLs than do "short" APs (C8, C10, C12). While current through all junctions showed a tunneling-like exponential length-attenuation, junctions with sparsely packed "short" AP MLs attenuate the current relatively more efficiently than those with densely packed, "long" ones. Furthermore, "long" AP ML junctions showed strong bias variation of the length decay coefficient, β, while for "short" AP ML junctions β is nearly independent of bias. Therefore, even for these simple molecular systems made up of what are considered to be inert molecules, the tunneling distance cannot be varied independently of other electrical properties, as is commonly assumed.

Original languageEnglish
Pages (from-to)404-415
Number of pages12
JournalLangmuir
Volume28
Issue number1
DOIs
StatePublished - 10 Jan 2012
Externally publishedYes

Fingerprint

Dive into the research topics of 'Molecular length, monolayer density, and charge transport: Lessons from Al-AlOx/alkyl-phosphonate/Hg junctions'. Together they form a unique fingerprint.

Cite this