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[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Terahertz Field Emission of Femto-Coulomb Electron Bunches
摘要： We demonstrate the sub-cycle optical field emission of electron wave packets with bunch charges up to 12 femtoCoulombs from a tungsten nanotip illuminated by intense THz pulses.
关键词： terahertz,field emission,tungsten nanotip,sub-cycle,electron bunches
更新于2025-09-10 09:29:36
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Simulation and experiment of field emission based on carbon nanotubes
摘要： In view of the bearing current of motor, a method of suppressing the bearing current using the ?eld emission characteristics of carbon nanotubes is proposed. Firstly, the advantages of carbon nano-materials and their ?eld emission properties are introduced. Secondly, the in?uence of the distance between the emitter tips and the anode metal plate on the electric ?eld intensity is analyzed by software simulation. Finally, ?eld emission experiments of TNF300 type carbon nanotube ?bers under non vacuum conditions were carried out by means of probes, microscopes and other experimental equipment. After obtaining the voltage and current of carbon nano-materials at di?erent distances, the volt-ampere characteristic curves and the ?eld emission characteristic curve were drawn, and the experimental results from di?erent distances were compared and analyzed.
关键词： carbon nanotubes,bearing current suppression,simulation and experiment,Field emission
更新于2025-09-10 09:29:36
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Comparison of mechanisms of the plasma generation by nanosecond discharge at extremely high overvoltage
摘要： Two mechanisms of the nanosecond timescale discharge initiation in nitrogen at extremely high overvoltage are compared using a one-dimensional Particle-in-Cell Monte Carlo collisions model. In the first mechanism, the discharge is ignited by the electrons seeded initially in the vicinity of the cathode, while in the second mechanism, the discharge is initiated by the electron field emission from the cathode. It was shown that both approaches predict discharge evolution governed by the runaway electrons generating in the cathode-anode gap. The latter promotes the propagation of the fast ionization wave from the cathode to the anode. However, there are some distinctive features which are explained by different numbers of runaway electrons presented in the cathode-anode gap. In the case, when the field emission is considered, one obtains the virtual cathode formation, the generation of electrons with the anomalous energy, and the fast ionization wave velocity comparable to the speed of light.
关键词： nanosecond discharge,runaway electrons,fast ionization wave,plasma generation,field emission
更新于2025-09-10 09:29:36
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A field emission performance test device for continuous adjustment of the electrode spacing in the vacuum system
摘要： This work presents a device that can adjust electrode spacing inside a vacuum system to evaluate the field emission characteristics of the carbon nanotube array cathode grown on a stainless steel substrate. It was made by coaxial connection of the rear end of a screw micrometer, which acts as the anode, with a stepper motor. The distance between the anode and the cathode was controlled by altering the pitch of the stepper motor with an angle precision of 1 degree. Therefore, the electrode separation can be tuned in the range of 0～15mm, at 1.388μm incremental steps. Comparing with devices with a fixed electrode spacing, the advantage is that this device allows continuous regulation of the electrode spacing after it is placed in a vacuum system to test the emission properties under various electrical parameters in one process thus avoiding repeated breaking of the vacuum environment. Therefore, test efficiency is improved, hence saving manpower, material resources, testing time and greatly reducing the cost of experimentation. This device is simple in structure and relatively easy to prepare.
关键词： Movable anode,Field emission,Carbon nanotubes,Vacuum system,Continuous regulation,Spiral micrometer
更新于2025-09-10 09:29:36
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Electrically Responsive Materials and Devices Directly Driven by the High Voltage of Triboelectric Nanogenerators
摘要： Smart materials with electrically responsive characteristics and devices relying on different electrostatic effects can be directly driven by triboelectric nanogenerators (TENGs). The open circuit voltage from a TENG can easily reach thousands of volts with a separation distance of a few millimeters and this high output voltage can be used to effectively drive or control some devices with high internal resistance. This kind of combination is the most straightforward way for achieving a self-powered smart system. Hence, a detailed survey of electrically responsive materials and devices that can be successfully combined with TENG is summarized, including dielectric elastomers, piezoelectric materials, ferroelectric materials, electrostatic manipulators, electrostatic air cleaners, and field emission and mass spectrometers. Moreover, key factors in determining suitable materials or devices to work with TENG are clarified and an in-depth discussion of the current challenges related to these combined systems is provided. With the cost-effectiveness and simple manufacturing process, these TENG-based composite systems have great application prospects in the field of smart mechanics, human–machine interaction systems, intelligent storage systems, self-powered microfluidic chips, portable mass spectrometers, and so on.
关键词： piezoelectric materials,mass spectrometers,electrostatic air cleaners,dielectric elastomers,electrically responsive materials,self-powered systems,field emission,electrostatic manipulators,triboelectric nanogenerators,ferroelectric materials
更新于2025-09-10 09:29:36
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission characteristics of individual ZnO nanowire before vacuum breakdown
摘要： The field emission characteristics of individual ZnO nanowire before breakdown were investigated. A current saturation was found during the pre-breakdown process. Mechanisms including the effects of joule heating, nanowire resistance and space charge effect have been considered. The analysis using simulation shows the phenomena could be related to space charge effect. However, more experimental and theoretical work should be carried out to pinpoint the exact mechanisms.
关键词： field emission,vacuum breakdown,ZnO nanowire,current saturation
更新于2025-09-10 09:29:36
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Metal–Air Transistors: Semiconductor-free field-emission air-channel nanoelectronics
摘要： Scattering-free transport in vacuum tubes has always been superior to solid-state transistors. It is the advanced fabrication with mass production capability at low cost which drove solid-state nano-electronics. Here, we combine the best of vacuum tubes with advanced nanofabrication technology. We present nano-scale, metal-based, field emission air channel transistors. Comparative analysis of tungsten, gold, and platinum based devices is presented. Devices are fabricated with electron beam lithography, achieving channel lengths less than 35 nm. With this small channel length, vacuum-like carrier transport is possible in air under room temperature and pressure. Source and drain electrodes have planar, symmetric and sharp geometry. Due to this, devices operate in bi-direction with voltages <2 V and current values in few tens of nA range. The experimental data shows that influential operation mechanism is Fowler–Nordheim tunnelling in tungsten and gold devices, while Schottky emission in platinum device. The presented work enables a technology where metal-based switchable nanoelectronics can be created on any dielectric surface with low energy requirements.
关键词： field emission,Air-channel transistor,semiconductor-free nanoelectronics,metal transistors
更新于2025-09-10 09:29:36
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Solution of the time dependent Schr?dinger equation leading to Fowler-Nordheim field emission
摘要： We solve the time-dependent Schr?dinger equation describing the emission of electrons from a metal surface by an external electric field E, turned on at t = 0. Starting with a wave function ψ(x, 0), representing a generalized eigenfunction when E = 0, we find ψ(x, t) and show that it approaches, as t → ∞, the Fowler-Nordheim tunneling wavefunction ψE(x). The deviation of ψ from ψE decays asymptotically as a power law t?3. The time scales involved for typical metals and fields of several V/nm are of the order of femtoseconds. We plot the short-time evolution of the current and density.
关键词： electron emission,time-dependent Schr?dinger equation,Fowler-Nordheim field emission,quantum tunneling
更新于2025-09-09 09:28:46
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Improved field emission from appropriately packed TiO2 nanorods: Designing the miniaturization
摘要： An improved electron field emission (FE) property from vertically aligned TiO2 nanorods (TNR) on conducting fluorine doped tin oxide coated glass substrate, prepared by hydrothermal technique, has been reported here. The TNRs having high aspect ratio with appropriate separation were prepared by optimizing the nucleation temperature. The TNR density has been optimized to cease the screening effect in closely packed nanorods. The well aligned rods have been designed so that the applied field is equally distributes on each rod to improve the electron emission. The morphology of the nanorod has been studied using scanning electron microscopy and observed FE current density-field response has been analysed within the frame work of Fowler-Nordheim modelling. Two orders of magnitude enhancement in the electric field has been observed for this kind of geometry giving improved turn on field and field enhancement factor of 0.2 V/m m and 37 thousands respectively.
关键词： Fowler-Nordheim modelling,Hydrothermal technique,Field emission,TiO2 nanorods,Field enhancement factor
更新于2025-09-09 09:28:46