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Atomic and Molecular Junction for Molecular Electronic Devices

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A special issue of Micromachines (ISSN 2072-666X).

Deadline for manuscript submissions: closed (30 April 2018) | Viewed by 23062

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Special Issue Editor

Prof. Manabu Kiguchi

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Guest Editor

Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
Interests: molecular electronics; single molecular junction; single molecular device; electron transport

Special Issue Information

Dear Colleagues,

The utilization of individual molecules as active electronic components is one of the dreams of human beings. If we can make an electronic device with a single atom and/or molecule, the size of computers and portable phones will be drastically reduced, and our lives will change. To realize molecular devices, we have to synthesize functional molecules, fix their physical properties, and integrate molecular devices in one tip. Therefore, researchers with different backgrounds: Physics, chemistry, and engineering, should work together. Molecular electronics is an interdisciplinary science.

The main target of molecular electronics is the molecular junction, where a single or few molecules bridge metal electrodes. Here, we have to take into account metal–molecule interactions. By connecting a molecule with metal electrodes, the character of the molecule changes from its original, due to orbital mixing and charge transfers at the metal–molecule interface. This makes molecular junctions complex. On the other hand, novel functionality can appear in this new material, which can lead to the creation of a new scientific field.

Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on molecular junctions, including basic physical properties of molecular junctions, single molecular devices, molecular sensing, and so on.

Prof. Manabu Kiguchi
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

molecular electronics
molecular junction
electron transport
single molecular device

Published Papers (6 papers)

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Research

Jump to: Review

10 pages, 4201 KiB

Open AccessArticle

Measuring Single-Molecule Conductance at An Ultra-Low Molecular Concentration in Vacuum

by Bo Liu, Makusu Tsutsui and Masateru Taniguchi

Micromachines 2018, 9(6), 282; https://doi.org/10.3390/mi9060282 - 3 Jun 2018

Cited by 5 | Viewed by 3088

Abstract

We report on systematic investigation of single-molecule detection mechanisms in break junction experiments in vacuum. We found molecular feature in the conductance traces at an extremely low concentration of molecules of 10 nM. This was attributed to condensation of the molecular solution on the junction surface upon evaporation of the solvent during evacuation. Furthermore, statistical analyses of the temporal dependence of molecular junction formation probabilities suggested accumulation effects of the contact mechanics to concentrate molecules absorbed on a remote area to the tunneling current sensing zone, which also contributed to the capability of molecular detections at the low concentration condition. The present findings can be used as a useful guide to implement break junction measurements for studying electron and heat transport through single molecules in vacuum. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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18 pages, 6663 KiB

Open AccessArticle

Towards Controlled Single-Molecule Manipulation Using “Real-Time” Molecular Dynamics Simulation: A GPU Implementation

by Dyon Van Vreumingen, Sumit Tewari, Fons Verbeek and Jan M. Van Ruitenbeek

Micromachines 2018, 9(6), 270; https://doi.org/10.3390/mi9060270 - 29 May 2018

Cited by 4 | Viewed by 3245

Abstract

Molecular electronics saw its birth with the idea to build electronic circuitry with single molecules as individual components. Even though commercial applications are still modest, it has served an important part in the study of fundamental physics at the scale of single atoms and molecules. It is now a routine procedure in many research groups around the world to connect a single molecule between two metallic leads. What is unknown is the nature of this coupling between the molecule and the leads. We have demonstrated recently (Tewari, 2018, Ph.D. Thesis) our new setup based on a scanning tunneling microscope, which can be used to controllably manipulate single molecules and atomic chains. In this article, we will present the extension of our molecular dynamic simulator attached to this system for the manipulation of single molecules in real time using a graphics processing unit (GPU). This will not only aid in controlled lift-off of single molecules, but will also provide details about changes in the molecular conformations during the manipulation. This information could serve as important input for theoretical models and for bridging the gap between the theory and experiments. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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Graphical abstract

8 pages, 2581 KiB

Open AccessArticle

Side-Group Effect on Electron Transport of Single Molecular Junctions

by Miao-Ling Huang, Fan Zhang, Chen Wang, Ju-Fang Zheng, Hui-Ling Mao, Hu-Jun Xie, Yong Shao, Xiao-Shun Zhou, Jin-Xuan Liu and Jin-Liang Zhuang

Micromachines 2018, 9(5), 234; https://doi.org/10.3390/mi9050234 - 13 May 2018

Cited by 8 | Viewed by 3729

Abstract

In this article, we have investigated the influence of the nitro side-group on the single molecular conductance of pyridine-based molecules by scanning tunneling microscopy break junction. Single molecular conductance of 4,4′-bipyridine (BPY), 3-nitro-4-(pyridin-4-yl)pyridine (BPY-N), and 3-nitro-4-(3-nitropyridin-4-yl)pyridine (BPY-2N) were measured by contact with Au electrodes. For the BPY molecular junction, two sets of conductance were found with values around 10^−3.1 G₀ (high G) and 10^−3.7 G₀ (low G). The addition of nitro side-group(s) onto the pyridine ring resulted in lower conductance of 10^−3.8 G₀ for BPY-N and 10^−3.9 G₀ for BPY-2N, respectively, which can be attributed to the twist angle of two pyridine rings. Moreover, the steric hindrance of nitro group(s) also affects the contacting configuration of electrode-molecule-electrode. As a consequence, only one set of conductance value was observed for BPY-N and BPY-2N. Our work clearly shows the important role of side-groups on the electron transport of single-molecule junctions. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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12 pages, 2237 KiB

Open AccessArticle

Theoretical Studies of the Spin-Dependent Electronic Transport Properties in Ethynyl-Terminated Ferrocene Molecular Junctions

by Shundong Yuan, Shiyan Wang, Zhaoyang Kong, Zhijie Xu, Long Yang, Diansheng Wang, Qidan Ling and Yudou Wang

Micromachines 2018, 9(3), 95; https://doi.org/10.3390/mi9030095 - 26 Feb 2018

Cited by 6 | Viewed by 3760

Abstract

The spin-dependent electron transport in the ferrocene-based molecular junctions, in which the molecules are 1,3-substituted and 1,3′-substituted ethynyl ferrocenes, respectively, is studied by the theoretical simulation with nonequilibrium Green’s function and density functional theory. The calculated results suggest that the substitution position of the terminal ethynyl groups has a great effect on the spin-dependent current-voltage properties and the spin filtering efficiency of the molecular junctions. At the lower bias, high spin filtering efficiency is found in 1,3′-substituted ethynyl ferrocene junction, which suggests that the spin filtering efficiency is also dependent on the bias voltage. The different spin-dependent transport properties for the two molecular junctions originate from their different evolutions of spin-up and spin-down energy levels. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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Graphical abstract

Review

Jump to: Research

14 pages, 437 KiB

Open AccessReview

Admittance of Atomic and Molecular Junctions and Their Signal Transmission

by Akira Sakai

Micromachines 2018, 9(7), 320; https://doi.org/10.3390/mi9070320 - 25 Jun 2018

Viewed by 2097

Abstract

Atom-sized contacts of metals are usually characterized by their direct current (DC) conductance. However, when atom-sized contacts are used as device interconnects and transmit high frequency signals or fast pulses, the most critical parameter is not their DC conductance but their admittance [...] Read more.

Y (ω)

, in particular its imaginary part

Im Y (ω)

. In this article, I will present a brief survey of theoretical and experimental results on the magnitude of

Y (ω)

for atom-sized contacts of metals. Theoretical contact models are first described and followed by numerical evaluation of

Im Y (ω)

based on these models. As for experiments on

Y (ω)

, previous experiments conducted under time-varying biases are surveyed, and then the results of direct signal transmission through atom-sized contacts are discussed. Both theoretical and experimental results indicate that

Im Y (ω)

is negligibly small for typical atom-sized contacts for signal frequencies up to 1 GHz. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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15 pages, 5160 KiB

Open AccessFeature PaperReview

Investigation on Single-Molecule Junctions Based on Current–Voltage Characteristics

by Yuji Isshiki, Yuya Matsuzawa, Shintaro Fujii and Manabu Kiguchi

Micromachines 2018, 9(2), 67; https://doi.org/10.3390/mi9020067 - 2 Feb 2018

Cited by 18 | Viewed by 6446

Abstract

The relationship between the current through an electronic device and the voltage across its terminals is a current–voltage characteristic (I–V) that determine basic device performance. Currently, I–V measurement on a single-molecule scale can be performed using break junction technique, where a single molecule junction can be prepared by trapping a single molecule into a nanogap between metal electrodes. The single-molecule I–Vs provide not only the device performance, but also reflect information on energy dispersion of the electronic state and the electron-molecular vibration coupling in the junction. This mini review focuses on recent representative studies on I–Vs of the single molecule junctions that cover investigation on the single-molecule diode property, the molecular vibration, and the electronic structure as a form of transmission probability, and electronic density of states, including the spin state of the single-molecule junctions. In addition, thermoelectronic measurements based on I–Vs and identification of the charged carriers (i.e., electrons or holes) are presented. The analysis in the single-molecule I–Vs provides fundamental and essential information for a better understanding of the single-molecule science, and puts the single molecule junction to more practical use in molecular devices. Full article

(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)

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