Download or read book Transport Properties of Molecular Junctions written by Natalya A. Zimbovskaya and published by Springer. This book was released on 2013-09-07 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the physical mechanisms that control electron transport and the characteristics of metal-molecule-metal (MMM) junctions. As far as possible, methods and formalisms presented elsewhere to analyze electron transport through molecules are avoided. This title introduces basic concepts--a description of the electron transport through molecular junctions—and briefly describes relevant experimental methods. Theoretical methods commonly used to analyze the electron transport through molecules are presented. Various effects that manifest in the electron transport through MMMs, as well as the basics of density-functional theory and its applications to electronic structure calculations in molecules are presented. Nanoelectronic applications of molecular junctions and similar systems are discussed as well. Molecular electronics is a diverse and rapidly growing field. Transport Properties of Molecular Junctions presents an up-to-date survey of the field suitable for researchers and professionals.
Download or read book Electron Transport Through Molecular Junctions written by Nataliya A. Zimbovskaya and published by . This book was released on 2011 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoscience And Technology A Collection Of Reviews From Nature Journals written by Peter Rodgers and published by World Scientific. This book was released on 2009-08-21 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains 35 review articles on nanoscience and nanotechnology that were first published in Nature Nanotechnology, Nature Materials and a number of other Nature journals. The articles are all written by leading authorities in their field and cover a wide range of areas in nanoscience and technology, from basic research (such as single-molecule devices and new materials) through to applications (in, for example, nanomedicine and data storage).
Download or read book Electron Transport Through Molecular Junctions written by Natal'ja A. Zimbovskaja and published by . This book was released on 2011 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Transport Through Porphyrin Molecular Junctions written by Qi Zhou and published by . This book was released on 2016 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Transport Through Single Molecular Junctions Molecular Wires and Switches written by Veerabhadrarao Kaliginedi and published by . This book was released on 2013 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser induced Electron Transport Through Molecular Junctions and DNA written by Guangqi Li and published by . This book was released on 2008 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this thesis is to investigate the electron transport through molecular junctions or wires which have recently attracted much attention experimentally as well as theoretically. Under the influence of a bias voltage and the coupling to the leads which act as electron source and drain, a current through the molecular junction is established. When an external time-dependent field, such as a laser field or an additional AC voltage is applied to the molecular junction, new features can be observed. One phenomenon is the well-known photon-assisted tunneling (PAT) which means that an external field periodic in time with frequency $omega$ can induce inelastic tunneling events when the electrons exchange energy quanta $hbar omega$ with the external field. Another important effect is the famous phenomenon of coherent destruction of tunneling (CDT) which exhibits the unusual effect of quenching the tunneling dynamics at specific values of the field amplitude. In the present thesis the theoretical foundation for these investigations is a density matrix formalism where the full system is partitioned into a relevant part, i.e. the molecular junctions and fermionic reservoirs mimicking the leads. By using a perturbative approach in the system-reservoir coupling strength, it is possible to establish a quantum master equation (QMEs) for the population dynamics of the wire states and an equation for the current through the wire. By combining the theory of optimal control and assuming a predefined target current, a laser field can be obtained which does generate a predefined current pattern. The same technique can be applied to minimize the shot noise. Besides of using QMEs to study electron transport through molecular junctions with the affection of a coupling to leads, it is also possible to apply QMEs to investigate the electron transfer through DNA which is coupled to a phonon-bath.
Download or read book Molecular Junctions for Nanoelectronics written by Swatilekha Saha and published by . This book was released on 2013 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elastic and Inelastic Electron Transport Through Alkane based Molecular Junctions written by and published by . This book was released on 2014 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport Properties of Molecular Junctions written by Natalya A. Zimbovskaya and published by Springer. This book was released on 2013-09-07 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the physical mechanisms that control electron transport and the characteristics of metal-molecule-metal (MMM) junctions. As far as possible, methods and formalisms presented elsewhere to analyze electron transport through molecules are avoided. This title introduces basic concepts--a description of the electron transport through molecular junctions—and briefly describes relevant experimental methods. Theoretical methods commonly used to analyze the electron transport through molecules are presented. Various effects that manifest in the electron transport through MMMs, as well as the basics of density-functional theory and its applications to electronic structure calculations in molecules are presented. Nanoelectronic applications of molecular junctions and similar systems are discussed as well. Molecular electronics is a diverse and rapidly growing field. Transport Properties of Molecular Junctions presents an up-to-date survey of the field suitable for researchers and professionals.
Download or read book Electron Transport Across Molecular Junctions written by Neeti Kapur and published by . This book was released on 2007 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: In conclusion, the electrical characteristics for a molecular device are dictated by the chemical functionality of the molecule bonded to the metal electrodes and the substituents attached. The electron flow can be further modified by variations in the device structure parameters and the molecular configurations, which realign the molecular energy states with respect to the reference metal Fermi levels.
Download or read book Electron Transport Through Single Molecular Junctions written by Chen Li and published by . This book was released on 2010 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Electronics An Introduction To Theory And Experiment written by Elke Scheer and published by World Scientific. This book was released on 2010-06-23 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the rapidly developing field of molecular electronics. It focuses on our present understanding of the electrical conduction in single-molecule circuits and provides a thorough introduction to the experimental techniques and theoretical concepts. It will also constitute as the first textbook-like introduction to both the experiment and theory of electronic transport through single atoms and molecules. In this sense, this publication will prove invaluable to both researchers and students interested in the field of nanoelectronics and nanoscience in general.Molecular Electronics is self-contained and unified in its presentation. It may be used as a textbook on nanoelectronics by graduate students and advanced undergraduates studying physics and chemistry. In addition, included are previously unpublished material that will help researchers gain a deeper understanding into the basic concepts involved in the field of molecular electronics.
Download or read book Approach to Control Protect and Switch Charge Transport Through Molecular Junctions and Atomic Contact written by Yong Ai and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular electronics has attracted increasing interest in the past decades. Constructing metal/molecules/metal junctions is a basic step towards the investigation of molecular electronics. We have witnessed significant development in both experiment and theory in molecular junctions. This thesis focuses mainly on the study of charge transport through molecular junctions. Conducting polymers and copper filaments were electrochemically deposited with a scanning electrochemical microscope (SECM) configuration between a tip and a substrate electrode. In doing so, we have developed a new way to fabricate atomic contact and molecular junctions, and we have explored the possibility to control, protect and switch these systems.Firstly, SECM, where two microelectrodes are located face-to-face separated by a micrometric gap, has been successfully used for the fabrication of redox-gated conducting polymers junctions, such as PEDOT and PBT. Highly stable and reversible redox-gated nano-junctions were obtained with conductance in the 10-7-10-8 S range in their conducting states. These results, associated with the wire-like growth of the polymer, suggest that the conductance of the entire junction in the conductive state is governed by less than 20 to 100 oligomers.Secondly, to obtain the nano-junctions in a controllable way, a break junction strategy combined with the SECM set up is adopted. A nano-junction could be acquired by pulling the tip away from its initial position. And conductance traces showed that PEDOT junctions can be broken step by step before complete breakdown. Similarly as STM-BJ conductance steps were observed on a PEDOT molecular junction before break down by using SECM-BJ. SECM break junction technique proved to be an efficient way of molecular junction fabrication studies, especially for redox gated polymer molecular junctions. Moreover, a self-terminated strategy is found to be another way to obtain nano-junctions. An external resistance connected to the electrode plays an important role in controlling the size of conducting polymer junctions.PFTQ and PFETQ molecular junctions exhibit well-defined ambipolar transport properties. However, an unbalanced charge transport properties in n- and p- channel for these two polymer junctions was observed when the junctions are in the fiber device scale. In contrast, when molecular junction changes into nano-junction, a balanced n- and p-channel transport property is acquired. We propose that such effect is due to charge transport mechanism changing from diffusive (ohm's law) to ballistic (quantum theory) when the junction size is reduced from fiber devices to nanodevices.High stable Au NPs/ITO electrodes exhibit a well localized surface plasmon (LSP) behavior. These plasmonic substrates have been successfully used to trigger switching of molecular junctions under light irradiation, demonstrating that surface plasmon resonance can induce electrochemical reduction. Such conductance reduction can be attributed to the hot electrons plasmonically generated from gold nanoparticles trapped into the PEDOT junction, resulting in PEDOT being reduced and changed to an insulating state.Finally, copper metallic nanowires were generated using an electrochemical self-terminated method based on SECM configuration. The presence of a few atoms that control the electron transport highlights the formation of metallic nanowires between the asymmetric electrodes. Furthermore, a similar study was performed on mesoporous silica film on ITO used as a substrate electrode. The mesoporous silica films have vertically aligned channels with a diameter of about 3 nm and a thickness of 115 nm, which play a crucial role in protecting the copper filament.
Download or read book Electron transport in molecular junctions written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design and Control of Highly Conductive Single Molecule Junctions written by Satoshi Kaneko and published by Springer. This book was released on 2017-04-04 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes improvements to and control of the electrical conductance in single-molecule junctions (SMJs), which have potential applications in molecular electronics, with a focus on the bonding between the metal and molecule. In order to improve the electrical conductance, the π orbital of the molecule is directly bonded to the metal orbital, because anchoring groups, which were typically used in other studies to bind molecule with metal electrodes, became resistive spacers. Using this direct π-binding, the author has successfully demonstrated highly conductive SMJs involving benzene, endohedral metallofullerene Ce@C82, and nitrogen. Subsequently, the author investigated control of the electrical conductance of SMJs using pyrazine. The nitrogen atom in the π-conjugated system of pyrazine was expected to function as an anchoring point, and two bonding states were expected. One originates primarily from the π orbital, while the other originates primarily from an n state of the nitrogen. Measurements of conductance and dI/dV spectra coupled with theoretical calculations revealed that the pyrazine SMJ has bistable conductance states, in which the pyrazine axis is either tilted or parallel with respect to the junction axis. The bistable states were switched by changing the gap size between the metal electrodes using an external force. Notably, it is difficult to change the electrical properties of bulk-state materials using mechanical force. The findings reveal that the electron transport properties of a SMJ can be controlled by designing a proper metal–molecule interface, which has considerable potential for molecular electronics. Moreover, this thesis will serve as a guideline for every step of SMJ research: design, fabrication, evaluation, and control.
Download or read book Electron Transport Energy Transfer and Optical Response in Single Molecule Junctions written by Alexander James White and published by . This book was released on 2014 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last decade has seen incredible growth in the quality of experiments being done on single molecule junctions. Contemporary experimental measurements have expanded far beyond simple electron transport. Measurement of vibronic effects, quantum interference and coherence effects, molecular optical response (Raman spectroscopy), and molecular spintronics are just some of the continuing areas of research in single molecule junctions. Experimental advancements demand advanced theoretical treatments, which can be used accurately within appropriate physical regimes, in order to understand measured phenomena and predict interesting directions for future study. In this dissertation we will study systems with strong intra-system interactions using a many-body states based approach. We will be focused on three related processes in molecular junctions: electron transport, electronic energy transfer, and molecular excitation. Inelastic electron transport in the regime of strong and nonlinear electron-vibration coupling within and outside of the Born-Oppenheimer regime will be investigated. To understand their appropriateness, we will compare simple semi-classical approximations in molecular redox junctions and electron-counting devices to fully quantum calculations based on many-body system states. The role of coherence and quantum interference in energy and electron transfer in molecular junctions is explored. Experiments that simultaneously measure surface enhanced Raman scattering and electron conduction have revealed a strong interaction between conducting electrons and molecular excitation. We investigate the role of the molecular response to a classical surface plasmon enhanced electric field considering the back action of the oscillating molecular dipole. Raman scattering is quantum mechanical by nature and involves strong interaction between surface plasmons in the contacts and the molecular excitation. We develop a scheme for treating strong plasmon-molecular excitation interactions quantum mechanically within nonequilibrium molecular junctions. Finally we perform preliminary calculations of the Raman spectrum of a three-ring oligophenylene vinylene terminating in amine functional groups molecule in a molecular junction and compare our results to experimental measurements. This work is the first steps towards full calculations of the optical response of current-carrying molecular junction, which should combine classical calculations of the plasmon enhanced electric field with quantum calculations for the plasmon-molecular exciton interaction and nonequilibrium Raman scattering.
