TY - JOUR
T1 - Molecular length, monolayer density, and charge transport
T2 - Lessons from Al-AlOx/alkyl-phosphonate/Hg junctions
AU - Levine, Igal
AU - Weber, Stephanie M.
AU - Feldman, Yishay
AU - Bendikov, Tatyana
AU - Cohen, Hagai
AU - Cahen, David
AU - Vilan, Ayelet
PY - 2012/1/10
Y1 - 2012/1/10
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84855662705&partnerID=8YFLogxK
U2 - 10.1021/la2035664
DO - 10.1021/la2035664
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:84855662705
SN - 0743-7463
VL - 28
SP - 404
EP - 415
JO - Langmuir
JF - Langmuir
IS - 1
ER -