scholarly journals Electrical Conductivity of Multiwall Carbon Nanotube Bundles Contacting with Metal Electrodes by Nano Manipulators inside SEM

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1290
Author(s):  
Quan Yang ◽  
Li Ma ◽  
Shungen Xiao ◽  
Dongxing Zhang ◽  
Aristide Djoulde ◽  
...  

Determining the metallicity and semiconductivity of a multi-walled carbon nanotube (MWCNT) bundle plays a particularly vital role in its interconnection with the metal electrode of an integrated circuit. In this paper, an effective method is proposed to determine the electrical transport properties of an MWCNT bundle using a current–voltage characteristic curve during its electrical breakdown. We established the reliable electrical nanoscale contact between the MWCNT bundle and metal electrode using a robotic manipulation system under scanning electron microscope (SEM) vacuum conditions. The experimental results show that the current–voltage curve appears as saw-tooth-like current changes including up and down steps, which signify the conductance and breakdown of carbon shells in the MWCNT bundle, respectively. Additionally, the power law nonlinear behavior of the current–voltage curve indicates that the MWCNT bundle is semiconducting. The molecular dynamics simulation explains that the electron transport between the inner carbon shells, between the outermost carbon shells and gold metal electrode and between the outermost carbons shells of two adjacent individual three-walled carbon nanotubes (TWCNTs) is through their radial deformation. Density functional theory (DFT) calculations elucidate the electron transport mechanism between the gold surface and double-wall carbon nanotube (DWCNT) and between the inner and outermost carbon shells of DWCNT using the charge density difference, electrostatic potential and partial density of states.

2014 ◽  
Vol 1697 ◽  
Author(s):  
Jie Liu ◽  
Xu Xu ◽  
M. P. Anantram

ABSTRACTThe sub-threshold electron transport properties of amorphous (a-) germanium telluride (GeTe) phase change material (PCM) ultra-thin films are investigated by using ab initio molecular dynamics, density function theory, and Green’s function simulations. The simulation results reproduce the trends in measured electron transport properties, e.g. current-voltage curve, intra-bandgap donor-like and acceptor-like defect states, and p-type conductivity. The underlying physical mechanism of electron transport in ultra-scaled a-PCM is unraveled. We find that, though the current-voltage curve of the ultra-scaled a-PCM resembles that of the bulk a-PCM, their physical origins are different. Unlike the electron transport in bulk a-PCM, which is governed by the Poole-Frenkel effect, the electron transport in ultra-scaled a-PCM is largely dominated by tunneling transport via intra-bandgap donor-like and acceptor-like defect states.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Mitchell B. Lerner ◽  
Brett Goldsmith ◽  
John Rockway ◽  
Israel Perez

It is critically important in designing RF receiver front ends to handle high power jammers and other strong interferers. Instead of blocking incoming energy or dissipating it as heat, we investigate the possibility of redirecting that energy for harvesting and storage. The approach is based on channelizing a high power signal into a previously unknown circuit element which serves as a passive intermodulation device. This intermodulation component must produce a hysteretic current-voltage curve to be useful as an energy harvester. Here we demonstrate a method by which carbon nanotube transistors produce the necessary hystereticI-Vcurves. Such devices can be tailored to the desired frequency by introducing functional groups to the nanotubes. These effects controllably enhance the desired behavior, namely, hysteretic nonlinearity in the transistors’I-Vcharacteristic. Combining these components with an RF energy harvester may one day enable the reuse of inbound jamming energy for standard back end radio components.


1994 ◽  
Vol 267 (4) ◽  
pp. C1095-C1102 ◽  
Author(s):  
J. J. Zhang ◽  
T. J. Jacob

In this report, we present the characteristics of a Cl- channel found in lens fiber cells. The single channel has a conductance of 17 pS, a linear current-voltage curve, is activated by ATP or strong depolarization and is blocked by verapamil, quinidine, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 5-nitro-2-(3- phenylpropylamino)benzoate, dideoxyforskolin, and tamoxifen. These properties are similar to those reported for a volume-activated Cl- channel associated with the multidrug resistance (MDR) gene product, P glycoprotein (24). Confirming this connection, we demonstrate that our lens Cl- channel is inhibited by an antibody to P glycoprotein. The data we present here may, therefore, be the first characterization of the single channel activity of the Cl- channel associated with P glycoprotein.


Author(s):  
Feng Gao ◽  
Jianmin Qu ◽  
Matthew Yao

The carbon nanotube (CNT) is becoming a promising candidate as electrical interconnects in nanoscale electronics. This paper reports the electronic structure and the electrical conducting properties at the interface between an open-end single wall CNT (SWCNT) and various metal electrodes, such as Al, Au, Cu, and Pd. A simulation cell consisting of an SWCNT with each end connected to the metal electrode was constructed. A voltage bias is prescribed between the left- and right-electrodes to compute the electronic conductance. Due to the electronic structure, the electron density and local density of states (LDOS) are calculated to reveal the interaction behavior at the interfaces. The first-principle quantum mechanical density functional and non-equilibrium Green’s function (NEGF) approaches are adopted to compute the transport coefficient. After that, the voltage-current relation is calculated using the Landauer-Buttiker formalism. The results show that electrons are conducted through the electrode/CNT/electrode two-probe system. The contact electronic resistance is calculated by averaging the values in the low voltage bias regime (0.0–0.1 V), in which the voltage–current relationship is found to be linear. And the electrical contact conductance of electrode/CNT/electrode system show the electrode-type dependent, however, the amplitude for different electrodes is of the same order.


1997 ◽  
Vol 467 ◽  
Author(s):  
D. Caputo ◽  
G. De Cesare ◽  
F. Palma

ABSTRACTA novel device based on a-Si:H p+-i-n−-i-p−-i-n+ structure, showing a hysteresis in its current-voltage curve is reported. A numerical device model allows to investigate in detail the fundamental role of the two lightly doped n− and p− layers, where charge trapping determines the bistable behavior of the device. The ON condition is mantained until the ambipolar charge injection overcomes the fixed charge. The transition OFF-ON starts when, increasing the applied voltage, one of the two lightly doped layers becomes completely depleted. The transition ON-OFF is, instead, mainly dependent on the recombination processes occurring in the central doped layers. Devices with hysteresis around 2 V and tum-on voltage around 12 are presented.


Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 22
Author(s):  
Anatoly N. Filippov ◽  
Natalia A. Kononenko ◽  
Natalia V. Loza ◽  
Daria A. Petrova

A novel bilayer cation-exchange membrane—consisting of a thick layer of a pristine perfluorinated membrane MF-4SC (Russian equivalent of Nafion®-117) and a thinner layer (1 μm) of the membrane, on a base of glassy polymer of internal microporosity poly(1-trimethylsilyl-1-propyne) (PTMSP)—was prepared and characterized. Using the physicochemical characteristics of one-layer membranes MF-4SC and PTMSP in 0.05 M HCl and NaCl solutions, the asymmetric current–voltage curves (CVC) of the bilayer composite were described with good accuracy up to the overlimiting regime, based on the “fine-porous membrane” model. The MF-4SC/PTMSP bilayer composite has a significant asymmetry of CVC that is promising for using it in electromembrane devices, such as membrane detectors, sensors, and diodes.


Author(s):  
Jonathan Cooper ◽  
Martin Scharm ◽  
Gary R Mirams

Computational modelling of cardiac cellular electrophysiology has a long history, with many models now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviours, in order to choose a model as a suitable basis for a new study, or characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models under a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models, and a website – https://chaste.cs.ox.ac.uk/FunctionalCuration – provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyper-kalaemia. This resource is publicly available, open source, and free; and we invite the community to use it and become involved in future developments. Those interested in comparing competing hypotheses using models can make a more informed decision; those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols.


2019 ◽  
Vol 14 (1) ◽  
pp. 1-6
Author(s):  
Li�gia Martins d'Oliveira ◽  
Valeriya Kilchytska ◽  
Denis Flandre ◽  
Michelly De Souza

This paper proposes a curve extraction method for I-V curves and analog figures-of-merit of self-cascode MOSFET associations (SC) using a code that exploits I-V curves of single transistors as input. The method was validated by using experimental measurements of fabricated SC and the very single transistors that compose them. The results indicate a very low error between the SC generated by the code and the measured reference for operation in saturation regime and above threshold voltage, for both the I-V curves and their derivatives. This method is then valid for the assessment of the SC structures in new technologies, avoiding experimental dedicated layouts or complex set-ups.


2018 ◽  
Vol 1 ◽  
pp. 94-98
Author(s):  
Israel Reyes-Ramírez ◽  
◽  
Jorge Fonseca-Campos ◽  
Juan Luis Mata Machuca

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