Single-molecule transistors

2015 ◽  
Vol 44 (4) ◽  
pp. 902-919 ◽  
Author(s):  
Mickael L. Perrin ◽  
Enrique Burzurí ◽  
Herre S. J. van der Zant
Keyword(s):  
Electric Field ◽  
Single Molecule ◽  
Gate Electrode ◽  
Single Molecule Transistor

Artist impression of a single-molecule transistor, where a molecule is connected to the source and the drain electrodes. The red lines illustrated the electric field caused by the gate electrode, located below.

Field Effect Modulation of Electrocatalytic Hydrogen Evolution at Back-Gated Two-Dimensional MoS2 Electrodes

2019 ◽  
Author(s):  
Yan Wang ◽  
Sagar Udyavara ◽  
Matthew Neurock ◽  
C. Daniel Frisbie
Keyword(s):  
Electric Field ◽  
Hydrogen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Electronic Charge ◽  
Back Side ◽  
Gate Electrode ◽  
Conventional Manner

<div> <div> <div> <p> </p><div> <div> <div> <p>Electrocatalytic activity for hydrogen evolution at monolayer MoS2 electrodes can be enhanced by the application of an electric field normal to the electrode plane. The electric field is produced by a gate electrode lying underneath the MoS2 and separated from it by a dielectric. Application of a voltage to the back-side gate electrode while sweeping the MoS2 electrochemical potential in a conventional manner in 0.5 M H2SO4 results in up to a 140-mV reduction in overpotential for hydrogen evolution at current densities of 50 mA/cm2. Tafel analysis indicates that the exchange current density is correspondingly improved by a factor of 4 to 0.1 mA/cm2 as gate voltage is increased. Density functional theory calculations support a mechanism in which the higher hydrogen evolution activity is caused by gate-induced electronic charge on Mo metal centers adjacent the S vacancies (the active sites), leading to enhanced Mo-H bond strengths. Overall, our findings indicate that the back-gated working electrode architecture is a convenient and versatile platform for investigating the connection between tunable electronic charge at active sites and overpotential for electrocatalytic processes on ultrathin electrode materials.</p></div></div></div><br><p></p></div></div></div>

scholarly journals Tuning Single-Molecule Conductance by Controlled Electric Field-Induced trans-to-cis Isomerisation

2021 ◽  
Vol 11 (8) ◽  
pp. 3317
Author(s):  
C.S. Quintans ◽  
Denis Andrienko ◽  
Katrin F. Domke ◽  
Daniel Aravena ◽  
Sangho Koo ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Single Molecule ◽  
Quantum Interference ◽  
Single Molecule Level ◽  
Wet Chemical Synthesis ◽  
Single Molecule Junctions ◽  
Tunnelling Microscopy ◽  
The Difference

External electric fields (EEFs) have proven to be very efficient in catalysing chemical reactions, even those inaccessible via wet-chemical synthesis. At the single-molecule level, oriented EEFs have been successfully used to promote in situ single-molecule reactions in the absence of chemical catalysts. Here, we elucidate the effect of an EEFs on the structure and conductance of a molecular junction. Employing scanning tunnelling microscopy break junction (STM-BJ) experiments, we form and electrically characterize single-molecule junctions of two tetramethyl carotene isomers. Two discrete conductance signatures show up more prominently at low and high applied voltages which are univocally ascribed to the trans and cis isomers of the carotenoid, respectively. The difference in conductance between both cis-/trans- isomers is in concordance with previous predictions considering π-quantum interference due to the presence of a single gauche defect in the trans isomer. Electronic structure calculations suggest that the electric field polarizes the molecule and mixes the excited states. The mixed states have a (spectroscopically) allowed transition and, therefore, can both promote the cis-isomerization of the molecule and participate in electron transport. Our work opens new routes for the in situ control of isomerisation reactions in single-molecule contacts.

Effect of Time Dependent Excitation Signals on Gating in Nanofluidic Channels

2015 ◽  
Author(s):  
C. Boone ◽  
M. Fuest ◽  
K. Wellmerling ◽  
S. Prakash
Keyword(s):  
Electric Field ◽  
Ionic Transport ◽  
Local Variation ◽  
Time Dependent ◽  
Local Perturbation ◽  
Gate Electrode ◽  
Nanofluidic Channels ◽  
Field Effect Devices ◽  
Dc Excitation ◽  
Dependent Signal

Nanofluidic field effect devices feature a gate electrode embedded in the nanochannel wall. The gate electrode creates local variation in the electric field allowing active, tunable control of ionic transport. Tunable control over ionic transport through nanofluidic networks is essential for applications including artificial ion channels, ion pumps, ion separation, and biosensing. Using DC excitation at the gate, experiments have demonstrated multiple current states in the nanochannel, including the ability to switch off the measured current; however, experimental evaluation of transient signals at the gate electrode has not been explored. Modeling results have shown ion transport at the nanoscale has known time scales for diffusion, electromigration, and convection. This supports the evidence detailed here that use of a time-dependent signal to create local perturbation in the electric field can be used for systematic manipulation of ionic transport in nanochannels. In this report, sinusoidal waveforms of various frequencies were compared against DC excitation on the gate electrode. The ionic transport was quantified by measuring the current through the nanochannels as a function of applied axial and gate potentials. It was found that time varying signals have a higher degree of modulation than a VRMS matched DC signal.

scholarly journals Breaching the Axial Limits in Ln(III) Single-Ion Magnets Using External Electric Field

2020 ◽  
Author(s):  
Arup Sarkar ◽  
Rajaraman Gopalan
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Barrier Height ◽  
Electric Fields ◽  
Single Molecule ◽  
Information Storage ◽  
Fine Tuning ◽  
Ligand Field ◽  
Nano Technology ◽  
Technology Applications

<i>Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (U<sub>eff</sub>). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)<sub>5</sub>(O<sup>t</sup>Bu)<sub>2</sub>]<sup>+</sup> (<b>1</b>) and [Er{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>Cl]<sup>-</sup> (<b>2</b>) and [Dy(Cp<sup>Me3</sup>)Cl] (<b>3</b>)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.</i>

Electric Field-induced switching among multiple conductance pathways in single-molecule junctions

2021 ◽  
Author(s):  
Tengyang Gao ◽  
Zhichao Pan ◽  
Zhuanyun Cai ◽  
Jueting Zheng ◽  
Chun Tang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Binding Sites ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Field Increase ◽  
Electric Field Increase ◽  
Single Molecule Junctions

Here, we report the switching among multiple conductance pathways achieved by sliding the scanning tunneling microscope tip among different binding sites under different electric fields. With the electric field increase,...

A single-molecule transistor in silicon

2014 ◽  
Author(s):  
M. Fernando Gonzalez-Zalba ◽  
Andre Saraiva ◽  
Maria J. Calderon ◽  
Dominik Heiss ◽  
Belita Koiller ◽  
...  
Keyword(s):  
Single Molecule ◽  
Single Molecule Transistor

scholarly journals How to control single-molecule rotation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Grant J. Simpson ◽  
Víctor García-López ◽  
A. Daniel Boese ◽  
James M. Tour ◽  
Leonhard Grill
Keyword(s):  
Electric Field ◽  
Single Molecule ◽  
Scanning Tunneling Microscope ◽  
Specific Interaction ◽  
Scanning Tunneling ◽  
Individual Molecule ◽  
Pivot Point ◽  
Dipolar Molecules ◽  
At Will ◽  
Orientation Of Molecules

Abstract The orientation of molecules is crucial in many chemical processes. Here, we report how single dipolar molecules can be oriented with maximum precision using the electric field of a scanning tunneling microscope. Rotation is found to occur around a fixed pivot point that is caused by the specific interaction of an oxygen atom in the molecule with the Ag(111) surface. Both directions of rotation are realized at will with 100% directionality. Consequently, the internal dipole moment of an individual molecule can be spatially mapped via its behavior in an applied electric field. The importance of the oxygen-surface interaction is demonstrated by the addition of a silver atom between a single molecule and the surface and the consequent loss of the pivot point.

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