Backbone of conductivity in two-dimensional metal-insulator composites (original) (raw)
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Applied Physics A: Materials Science & Processing, 1999
Results of investigation of electrical properties of metal-polymer-metal (MPM) structures are presented. It was found that the MPM structures exhibit non-ohmic behaviour in a broad interval of applied electrical fields. In order to reveal the mechanism of electrical charge transport, the temperature dependence of the dielectric constant of polymer was examined on the polymer phases. The interpretation of the observed dependences according to Schottky and Pool-Frenkel conductivity models was considered.
Electric conductivity of organic films, containing nanosize metal particles
Materials Science and Engineering: C, 1999
. New materials, containing nanodispersed particles Ag, Pb, Mn, Ca, Sm, Na, CdS, ZnS in the thin polymer film have been obtained Ž . via low temperature codeposition of metal or sulphide with reactive para-xylylene monomer vapours at 100 K. Electric conductivity of the films was studied during the components co-condensation, upon sample annealing in range 80-300 K and maintaining at constant temperature. With a rise of metal nanoparticles in the polymer matrix, the conductivity tends to increase. The conductivity may be Ž . determined as a tunnel transfer of charge from one nanoparticle to another through a thin dielectric layer up to 50 nm of polymer matrix. q 1999 Elsevier Science S.A. All rights reserved.
Conductivity of island metal films covered with organic molecules
Journal of Molecular Structure, 2004
Experimental data were obtained on the effect of adsorbed organic molecules (naphthalene, stearone, benzene, xylene, aluminum oxyquinoline and mixtures of some aliphatic compounds) on the conductivity of gold island films. Nanoisland structures were realized which exhibit non-linear conduction current-voltage characteristics and a sharp switching effect in the presence of adsorbed organics. The conditions for the occurrence of the voltage-controlled negative resistance in such nanocomposite systems are discussed. Some data are also given on electroluminescence of the nanocomposites. Two theoretical models are suggested to describe the conduction current-voltage characteristics of organic molecular structures under various conditions.
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Bulletin of Materials Science, 2014
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NATO Science for Peace and Security Series B: Physics and Biophysics, 2012
Cluster approach based on the multiple scattering theory formalism, realistic analytical and coherent potentials, as well as effective medium approximation (EMA-CPA), can be effectively used for nano-sized systems modeling. Major attention is paid now to applications of carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) with various morphology which possess unique physical properties in nanoelectronics, e.g., contacts of CNTs or (GNRs) with other conducting elements of a nanocircuit, which can be promising candidates for interconnects in high-speed electronics. The main problems solving for resistance C-Me junctions with metal particles appear due to the influence of chirality effects in the interconnects of single-wall (SW) and multi-wall (MW) CNTs, single-layer (SL) and multi-layer (ML) GNRs with the fitting metals (Me ¼ Ni, Cu, Ag, Pd, Pt, Au) for the predefined carbon system geometry. Using the models of 'liquid metal' and 'effective bonds' developed in the framework of the presented approach and Landauer theory, we can predict resistivity properties for the considered interconnects. We have also developed the model of the inter-wall interaction inside MW CNTs, which demonstrates possible 'radial current' losses. CNT-and GNR-Metal interconnects in FET-type nanodevices provide nanosensoring possibilities for local physical (mechanical), chemical and biochemical influences of external medium. At the same time, due to high In order to overcome disadvantages of nowadays microtechnology, the miniaturization of electronic devices, the integration level expansion and the increase of the operation frequencies and power density are required, including the use of adequate materials and innovative chip interconnects. Due to their unique physical properties, especially due to a ballistic mechanism of conductivity, carbon nanotubes (CNTs) attract a permanently growing technological interest, for example, as promising candidates for nanointerconnects in high-speed electronics [1]. New possibilities for modern nanolectronics are open with novel 'marginal' forms of graphene -nanoflakes (GNFs) and nanoribbons (GNRs), which in analogy with CNTs demonstrate a wasteless ballistic mechanism of conductivity. Graphene nanointerconnects are also important for nanotechnology. Full integration of graphene into conventional device circuitry would require a reproducible large scale graphene synthesis that is compatible with conventional thin film technology.
Nanoscale contacts between semiconducting nanowires and metallic graphenes
Applied Physics Letters, 2012
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Results in Physics, 2022
The present work studied the scalability of phase change material (PCM) down to a single-digit nm with single wall metallic carbon nanotubes (SWCNT) electrodes. For this purpose, the low bias electron transport properties of Ge 2 Sb 2 Te 5 (GST) are investigated using a DFT-NEGF formalism. The amorphous Ge 2 Sb 2 Te 5 (a-GST) is obtained using DFT-based molecular dynamic simulation. It has been seen that while 6 nm crystalline Ge 2 Sb 2 Te 5 (c-GST) has a large transmission near the Fermi level, a-GST exhibits a clear band-gap, and by further reduction of its length to 12 Å, the band-gap disappears. The electrical conductance of nanowire a-GST is predominantly due to coherent electron transport via acceptor-like and donor-like traps. The c-GST/a-GST conductance (c ∕ a) ratio as a function of the device length is calculated, which shows good agreement compared with experimental works. We show that the ultimate limit for downscaling the nanowire GST sandwiched between SWCNT electrodes is about 24 Å. This can be attributed to the overlapping metalinduced gap states from electrodes that lead to the disappearance of the band-gap of the amorphous phase and a sharp decrease in the c ∕ a ratio in shorter channel length. The On/Off ratio of 12 Å GST sharply drops below 10, and the reliable read procedure is not possible on this size scale. We have also investigated the effect of interfacial stress between the electrode and GST and show that it reduces the c ∕ a ratio and hurts the switch-ability of the device.
Applied Physics Letters, 2012
We demonstrate the ability of first row transition metals to form electrically conducting interconnects between semiconducting single-walled carbon nanotubes (SWNTs) by constructive rehybridization between sidewall benzene rings as a result of the formation of bis-hexahaptometal-bonds [(g 6 -SWNT)M(g 6 -SWNT)], which bridge adjacent SWNTs. Metal deposition on SWNT films enhances the conductivity by three distinct mechanisms: physisorption of gold leads to the formation of a non-interacting gold film and a monotonic conductivity increase; ionic chemisorption of lithium strongly increases the conductivity due to charge transfer to the SWNTs; covalent chemisorption of first row transition metals leads to an abrupt change in conductivity due to formation of (g 6 -SWNT)M(g 6 -SWNT) interconnects. V C 2012 American Institute of Physics.
Journal of Applied Physics, 1999
Metal/polymer Schottky contacts have been fabricated using electrochemically prepared free standing thin films of conducting polyaniline/polycarbonate composite as well as conducting polyaniline pellets with various metals such as Al, In, Pb and Sn. The current-voltage characteristics have been studied from room temperature down to 100 K. The data have been analyzed and interpreted on the basis of the thermionic emission mechanism. The barrier height varies from 0.6 to 0.7 V for pellet and from 0.7 to 0.8 V for composite films. There is little dependence of metal on the work function. The ideality factor is dependent on the amount of polyaniline incorporation in polycarbonate, as indicated by the shift in the carbonyl peak in the Fourier transform infrared spectrum. The abnormal decrease in barrier height and increase of ideality factor with decrease in temperature have been interpreted assuming a Gaussian distribution of barrier heights at the interface. This takes account of the nonuniformity and inhomogeneities at the interface. As in the case of inorganic semiconductor diodes, the analysis indicates an apparent decrease in zero bias height and nonlinearity in activation plots. The bias dependence of barrier height and standard deviation causing an increase in ideality factor at low temperature has also been explored.