A Bond-Fluctuation Mechanism for Stochastic Switching in Wired Molecules

Ramachandran, Ganesh K.; Hopson, Theresa; Rawlett, Adam M.; Nagahara, Larry A.; Primak, A.; Lindsay, Stuart

doi:10.1126/science.1083825

Cited by 407 publications

(399 citation statements)

References 21 publications

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“…The top electrode could be metal nanoclusters prepared by vacuum vapor deposition [1][2][3][4][5][6][7][8][9][10] or from a suspension of metal nanoparticles. [11][12][13][14] Previous studies have shown that vapor-deposited Au or Ag penetrates into the SAM and inserts into the thiol-Au bond at the Au/ SAM interface when it is vacuum-deposited on an alkanethiol SAM with a methyl end group. 2,3,[5][6][7] In contrast, when they are deposited on an alkanedithiol SAM with a thiol end group pointing up, metal nanoparticles are formed on top of the SAM.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

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Electrochemical deposition of metals (platinum or gold) only on top of an organothiolate, 1,4-benzenedimethanethiol (BDMT) or hexanedithiol (HDT), self-assembled monolayer (SAM) on a Au(111) substrate was achieved by electrochemical reduction of PtCl 4 2-or AuCl 4 -ion, which was preadsorbed on one free thiol end group of the dithiol SAM formed on a Au surface, in a metal-ion-free sulfuric acid solution at potentials more negative than the reduction potential of the metal ion. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) measurement after the reduction of preadsorbed PtCl 4 2-ion on BDMT/Au(111) electrode showed the presence of Pt not underneath but on top of the BDMT SAM. After a negative potential scan of the Pt/BDMT/Au(111) electrode to -1.30 V in 0.1 M KOH solution, a typical cyclic voltammogram of a clean Au(111) electrode was obtained, showing that the BDMT SAM with a Pt layer was reductively desorbed. These results proved that a Pt-BDMT SAM-Au substrate sandwich structure without a short circuit between the two metals was successfully constructed by this technique. Furthermore, a decanethiol (DT) monolayer was constructed on a Au layer, which was formed by the reduction of preadsorbed AuCl 4 -ion on HDT/Au(111) electrode. The formation of DT/Au/HDT/Au(111) structure was confirmed as two cathodic peaks corresponding to reductive desorption of DT from Au on top of the HDT/Au(111) at -0.97 V and that of Au/ HDT from Au(111) at -1.12 V were observed when potential was scanned negatively to -1.35 V.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

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“…Many research efforts are probing the unique charge-transport properties of individual molecules with hopes of revolutionizing electronics and computation. A common experimental approach in this field is to vary the structure of the organic molecule that is placed between two metal electrodes (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). However, recent reports suggest that the contacts themselves play a pivotal role in the observed charge-transport behavior of several of these devices (15).…”

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confidence: 99%

Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy

Guisinger

Yoder

Hersam

2005

Proc. Natl. Acad. Sci. U.S.A.

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A cryogenic variable-temperature ultra-high vacuum scanning tunneling microscope is used for measuring the electrical properties of isolated cyclopentene molecules adsorbed to the degenerately p-type Si(100)-2؋1 surface at a temperature of 80 K. Currentvoltage curves taken under these conditions show negative differential resistance at positive sample bias, in agreement with previous observations at room temperature. Because of the enhanced stability of the scanning tunneling microscope at cryogenic temperatures, repeated measurements can be routinely taken over the same molecule. Taking advantage of this improved stability, we show that current-voltage curves on isolated cyclopentene molecules are reproducible and possess negligible hysteresis for a given tip-molecule distance. On the other hand, subsequent measurements with variable tip position show that the negative differential resistance voltage increases with increasing tipmolecule distance. By using a one-dimensional capacitive equivalent circuit and a resonant tunneling model, this behavior can be quantitatively explained, thus providing insight into the electrostatic potential distribution across a semiconductor-moleculevacuum-metal tunnel junction. This model also provides a quantitative estimate for the alignment of the highest occupied molecular orbital of cyclopentene with respect to the Fermi level of the silicon substrate, thus suggesting that this experimental approach can be used for performing chemical spectroscopy at the single-molecule level on semiconductor surfaces. Overall, these results serve as the basis for a series of design rules that can be applied to silicon-based molecular electronic devices.cyclopentene ͉ resonant tunneling ͉ molecular electronics ͉ capacitance ͉ spectroscopy S ince the seminal paper of Aviram and Ratner (1), the field of molecular electronics has undergone rapid growth. Many research efforts are probing the unique charge-transport properties of individual molecules with hopes of revolutionizing electronics and computation. A common experimental approach in this field is to vary the structure of the organic molecule that is placed between two metal electrodes (2-14). However, recent reports suggest that the contacts themselves play a pivotal role in the observed charge-transport behavior of several of these devices (15). This development suggests that, in addition to different molecular systems, alternative contact materials may lead to unique electronic functionality. Because of its compatibility with organic chemistry, its semiconductor band structure, and its ubiquity in commercially available microelectronics, silicon is a promising alternative substrate for molecular electronics.Concurrent with the recent developments in molecular electronics, the ultra-high vacuum (UHV) scanning tunneling microscope (STM) has advanced well beyond its original purpose of probing the structure and properties of materials at atomic length scales (16). Atom manipulation (17-21), nanolithography (22-25), chemical modification (2...

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“…If two disconnected parts of a conducting molecular chain are connected by a bond with two coupled potential energy surfaces with 2 degrees of freedom, the resulting chain will reveal nonlinear characteristics [3,4]. It has been shown experimentally in a scanning tunneling microscopy (STM) that these kinds of molecules switch between two potential energy minima and function as nanomolecular switches [5][6][7]. It has been suggested that excitation by an applied electric field [8] or a laser field [3] is the trigger for the molecular switch and resultant conformational change (CC) [ Fig.…”

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confidence: 99%

Conformational Molecular Switch of the Azobenzene Molecule: A Scanning Tunneling Microscopy Study

et al. 2006

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We propose to utilize azobenzene as a nanomolecular switch which can be triggered by transmitting electrons above threshold biases. The effect is explained by an electron impact trans-cis conformational change of the isolated azobenzene molecules. The molecular electronic states of both isomers have been measured with spatially resolved scanning tunneling microscopy or spectroscopy, leading to suggested transition pathways of the electron-induced isomerization.

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A Bond-Fluctuation Mechanism for Stochastic Switching in Wired Molecules

Cited by 407 publications

References 21 publications

Electrochemical Metal Deposition on Top of an Organic Monolayer

Electrochemical Metal Deposition on Top of an Organic Monolayer

Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy

Conformational Molecular Switch of the Azobenzene Molecule: A Scanning Tunneling Microscopy Study

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