Electrical Conductance of Molecular Junctions by a Robust Statistical Analysis

González, M. Teresa; Wu, Songmei; Huber, R.; Molen, Sense Jan van der; Schönenberger, Christian; Calame, Michel

doi:10.1021/nl061581e

Cited by 194 publications

(265 citation statements)

References 30 publications

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“…The mean value of the apparent tunneling barrier height before the plateau is 0.6-1.0 eV, which can be attributed to tunneling through the SAM. After the molecular bridge breaks, the conduction mechanism is due to vacuum tunneling under ambient conditions 19 and the mean barrier height is 1.0-2.4 eV. The fact that the apparent tunneling barrier height is lower when the tip is in contact with the SAM is in good agreement with previous work in which a lowering of the apparent barrier height is suggested due to the elastic surface deformation induced by the repulsive forces during the tip-sample contact.…”

supporting

confidence: 90%

Carbon tips as electrodes for single-molecule junctions

Castellanos-Gómez

Bilan

Zotti

et al. 2011

Applied Physics Letters

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The following article appeared in Applied Physics Letters vol 99,12 (2011): 123105 and may be found at http://scitation.aip.org/content/aip/journal/apl/99/12/10.1063/1.3643031?showFTTab=true&containerItemId=content/aip/journal/aplWe study electron transport through single-molecule junctions formed by an octanethiol molecule bonded with the thiol anchoring group to a goldelectrode and the opposing methyl endgroup to a carbon tip. Using the scanning tunneling microscope based break junction technique, we measure the electrical conductance of such molecular junctions. We observe the presence of well-defined conductance plateaus during the stretching of the molecular bridge, which is the signature of the formation of a molecular junction.Acknowledges fellowship support from the Comunidad de Madrid (Spain). This work was supported by MICINN (Spain) through the programs MAT2008-01735 and CONSOLIDER-INGENIO-2010 CSD-2007-00010, by Comunidad de Madrid through the program NANOBIOMAGNET S2009/MAT1726, by the EU through the networks BIMORE (MRTN-CT-2006-035859),and by the EC through the network FP7 ITN “FUNMOLS”Project Number 212942

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supporting

confidence: 90%

Carbon tips as electrodes for single-molecule junctions

Castellanos-Gómez

Bilan

Zotti

et al. 2011

Applied Physics Letters

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“…In general, the possible experimental setups can be divided into two main categories: mechanically controlled break-junctions (MCBJs) [1][2][3][4]6,8,9,[17][18][19] and scanning tunneling microscopy (STM) experiments. 5,7,[20][21][22][23][24][25][26][27][28][29] In the former, a gold nano-contact is created by stretching a gold wire and, just before rupture, a solution containing the target molecules is added to the system.…”

Section: Introductionmentioning

confidence: 99%

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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It is often assumed that the hydrogen atoms in the thiol groups of a benzene-1,4-dithiol dissociate when Au-benzene-1,4-dithiol-Au junctions are formed. We demonstrate, by stability and transport property calculations, that this assumption cannot be made. We show that the dissociative adsorption of methanethiol and benzene-1,4-dithiol molecules on a flat Au(111) surface is energetically unfavorable and that the activation barrier for this reaction is as high as 1 eV. For the molecule in the junction, our results show, for all electrode geometries studied, that the thiol junctions are energetically more stable than their thiolate counterparts. Due to the fact that density functional theory (DFT) within the local density approximation (LDA) underestimates the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital by several electron-volts, and that it does not capture the renormalization of the energy levels due to the image charge effect, the conductance of the Au-benzene-1,4-dithiol-Au junctions is overestimated. After taking into account corrections due to image charge effects by means of constrained-DFT calculations and electrostatic classical models, we apply a scissor operator to correct the DFT energy level positions, and calculate the transport properties of the thiol and thiolate molecular junctions as a function of the electrode separation. For the thiol junctions, we show that the conductance decreases as the electrode separation increases, whereas the opposite trend is found for the thiolate junctions. Both behaviors have been observed in experiments, therefore pointing to the possible coexistence of both thiol and thiolate junctions. Moreover, the corrected conductance values, for both thiol and thiolate, are up to two orders of magnitude smaller than those calculated with DFT-LDA.This brings the theoretical results in quantitatively good agreement with experimental data.

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“…We have been exploiting this technique extensively over the past years to determine some of the basic mechanisms at stake in the formation of molecular junctions. [21][22][23][24][25][26][27][28][29] Some examples are provided in the next section.…”

Section: Contacting Strategiesmentioning

confidence: 99%

“…The conductance is plotted as a function of the vertical displacement of the push-rod z and shown in a logarithmic scale in order to provide a full view of its evolution during an opening cycle. [22] The ratio between the horizontal elongation of the metallic bridge and the vertical push-rod displacement obtained for microfabricated junctions reaches typically 10 -5 , giving them an excellent mechanical stability. [20,22] A vertical displacement of 1 mm will thus result in a 10 pm gap widening.…”

Section: Assembling a Molecular Junctionmentioning

confidence: 99%

“…[22] The ratio between the horizontal elongation of the metallic bridge and the vertical push-rod displacement obtained for microfabricated junctions reaches typically 10 -5 , giving them an excellent mechanical stability. [20,22] A vertical displacement of 1 mm will thus result in a 10 pm gap widening. During bending and opening of the gap, the conductance G(z) decreases, showing a series of conductance plateaus for G values above the quantum conductance unit G 0 = 2⋅e 2 /h (arrow in Fig.…”

Section: Assembling a Molecular Junctionmentioning

confidence: 99%

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Molecular Junctions: From Tunneling to Function

Calame

2010

Chimia

Self Cite

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Abstract:Thankstothedevelopmentofappropriateexperimentaltechniques,moleculardevicesandtheirelectricaltransportpropertieshaverecentlybeenthefocusofamajorresearcheffort.Thisbriefreviewdescribeshow individualmoleculescanbecontactedwithmetallicelectrodestoformmolecularjunctionsandaddressestheir basicformationmechanisms.Anextensiontomolecularjunctionsnetworksisalsodiscussed.Functionalitycould bedemonstratedinsuchsystems,andexampleswhereconductancemodulationusinglightorchemicalstimuli wasachievedwillbepresented.

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Electrical Conductance of Molecular Junctions by a Robust Statistical Analysis

Cited by 194 publications

References 30 publications

Carbon tips as electrodes for single-molecule junctions

Carbon tips as electrodes for single-molecule junctions

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Molecular Junctions: From Tunneling to Function

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