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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) - Comparison of experimental and theoretical methods for determining the emission area of multitip field cathodes
摘要： The experimental and theoretical methods for obtaining the values of the emitting surface are considered. The obtained values of the emission area from the experimental current-voltage characteristic are compared with those derived using theoretical calculations and computer simulation.
关键词： Fowler-Nordheim plots,emission area,current-voltage data analysis,single walled carbon nanotubes,glow patterns,multi-tip field emitter
更新于2025-09-23 15:21:21
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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) - Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup
摘要： The influence of residual gas pressure on the characteristics of black-Silicon field emitter arrays in a high voltage triode setup is investigated. I-V-characteristics at different pressure levels show a decrease of emission current with rising pressure. This can be explained by an increase of the work function and charging of the emitter surface due to adsorbates. The initial characteristics can be restored by heating the FEA up to 110 °C during electron emission. This regeneration procedure enables an extension of the lifetime from about 20 h to 440 h at a residual gas pressure of 10-5 mbar.
关键词： silicon tips,emission current stability,semiconductor field emission,field emitter array
更新于2025-09-23 15:21:21
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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) - Experimental Definition of k-power of Pre-Exponential Voltage Factor for LAFE
摘要： In this work we used the possibilities of a comprehensive research methodology for LAFE. To determine the degree of the voltage in the pre-exponential factor, we used the IVC differentiation method and the method of minimization trend residue by variation Fowler-Nordheim coordinates. The method proved to be very sensitive to IVC bends and can serve as a characteristic for the homogeneity of LAFE arrays.
关键词： k-power,nanocomposite,field emission,carbon nanotubes,differentiation of current-voltage charateristics
更新于2025-09-23 15:21:21
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DC-Bus Dual-Level Control Strategy for PV Power System with Dual-Mode Operation
摘要： An autonomous dc-bus dual-level control (DDLC) strategy is proposed for the two-stage three-phase photovoltaic (PV) power system. During the grid-fault situation, the second-stage inverter may lose the ability to regulate the dc-bus voltage and the first-stage boost converter has to change its mode from maximum power point tracking (MPPT) mode to dc-bus voltage control (DCVC) mode. However, the communication between the two-stage circuits must be established. The circuit complexity and cost will increase while the system’s scalability and flexibility will be reduced. With the proposed DDLC strategy, the dc-bus voltage is controlled into different levels for different operation modes, without the need of communication mechanism. No extra sensors or circuits are required. Two important design parameters for the proposed DDLC are derived thoroughly. The computer simulations and hardware experimental results of a 4 kVA prototype circuit are presented to validate the performance of the proposed DDLC strategy.
关键词： Optimal AC Line Current Regulation,Maximum Power Point Tracking (MPPT),PV Power System,DC-Bus Voltage Control (DCVC)
更新于2025-09-23 15:21:21
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Broadband Antennas with Reactive Loads
摘要： The results of a study on the expansion of the frequency range of vibrational curved whip and loop antennas are presented. Optimal designs of these antennas with concentrated reactive loads included in the shoulders are proposed. The study was carried out for a design that appears promising for use as a microstrip antenna. It is a Z-shaped antenna of orthogonal linear polarization and loop antenna, supplemented by concentrated capacitive loads. It is shown that in order to obtain in the Z-shaped antenna and loop antenna a regime of a current close to the traveling wave regime and to obtain broadband, it is sufficient to include no more than four capacitive loads of a certain value in the antenna arm. This makes the construction of a broadband antenna and to reduce the expenditure of time and resources for its development and fabrication in comparison with known works in which it was proposed to include in the arm of the antenna a much larger number of reactive loads.
关键词： concentrated capacitive load,distribution of the complex current at the antenna,broadband antenna,standing wave voltage factor,antenna gain factor
更新于2025-09-23 15:21:21
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Monte Carlo Modeling of the Diodes with Lateral Resonant Tunneling Border
摘要： Diodes with resonant tunneling border (RTB) are studied as possible high speed and wide-band devices. The diodes represent planar two-terminal n+-n-n+-GaAs-based structures containing lateral active border as a AlGaAs/GaAs double barrier resonant tunneling structure connected to anode contact. The 2-D model of electron transport in the device is proposed. The analysis of the diodes operation was performed using ensemble Monte Carlo technique. Transfer matrix approach for simulation of tunneling transfer is applied. The influence of parameters of the diode structure such as a position of RTB, a composition of AlGaAs barriers and a material doping on current – voltage characteristics of diode has been investigated. strong influence of contact size and geometry on the diode characteristic. The aim of the work is to construct an effective numerical 2D model used to consider electron transport at high frequencies with taking into account hot-carrier effects in cases where the mean free path is comparable to the device dimensions and electron tunneling processes are in place. The basis of the proposed model is ensemble Monte Carlo method [4]. The other model elements are chosen by obtaining accurate physical results per reasonable time.
关键词： negative voltage current differential resistance,characteristics,heterojunction,quantum well,resonant tunneling border
更新于2025-09-23 15:21:21
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Identification of spherical and non-spherical protein by solid-state nanopore
摘要： Three-dimensional structure of a protein plays an important role in protein dynamics in biological system of human. By now, it remains challenge to characterize and quantify the shape of a protein at single-molecule level. Nanopore, as a novel single-molecule sensor, has been widely applied in many fields such as DNA sequencing and human diseases diagnosis. In this paper, we investigated the translocation of sphere-like con.A and the prolate Bovine Serum Albumin (BSA) under electric field by solid-state nanopore. By analyzing the ionic current, the con.A and the BSA could be characterized and differentiated due to their intrinsic shape difference. Because the prolate BSA will have the preferred orientations for higher electric field when it is residing inside the nanopore, thus multiple ionic current blockade levels will be observed. While for the spherical con.A, there is only one ionic current blockade level. This method presented here will be potentially applied to fingerprint a single protein as a new method having features of low-cost and high-throughput in the near future.
关键词： orientation,solid-state nanopore,shape,electric field,ionic current,protein
更新于2025-09-23 15:21:21
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DC and RF characteristics optimization of AlGaN/GaN/BGaN/GaN/Si HEMT for microwave-power and high temperature application
摘要： AlGaN/GaN/Si high electron mobility transistors (HEMTs) developed by molecular beam epitaxy (MBE) are studied with several methods for characterization, the most utilized are direct-current and radio-frequency measurements, to see power and microwave performance of components. The increase in these parameters is not based just with on improvement technological for example, decrease of length gate (Lg) and passivation. For sure, another very important point is to reduce the thickness of barrier while keeping the reduction in the length of gate, in order to reduce the transit time (τ), and consequently access to highest cut-o? frequency (FT). For this situation, it’s appears a harmful phenomenon of type “punch-through”, because of the weak con?nement of electrons in the channel. In this paper, the main objective is to show how to reduce this e?ect.
关键词： HEMT GaN,Radio-frequency,Current-voltage characteristics,RF characteristics,Alloys BGaN
更新于2025-09-23 15:21:21
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Simultaneous scanning ion conductance and atomic force microscopy with a nanopore: Effect of the aperture edge on the ion current images
摘要： Scanning ion conductance microscopy (SICM) is a technique for high-resolution non-contact imaging, particularly powerful for live cell studies. Despite debates on its lateral resolution, consensus is that a probe presenting a tip with small opening aperture, large opening angle, and large outer-to-inner radius ratio will offer a SICM current signal more sensitive to tip-sample separation, ultimately impacting the image resolution. We report here the design of such a probe, integrating a nano-opening (<20 nm opening diameter) with increased outer-to-inner radius ratio and a wide opening angle through microfabrication and ion milling. The probe consists of a microfluidic atomic force microscopy (AFM) cantilever offered by the Fluid Force Microscope (FluidFM) technology, able to act as an SICM and AFM probe. Such a combination allows investigating the implications of the new probe geometry on the SICM imaging process by simultaneously recording currents and forces. We demonstrate through experiments on well-defined samples as well as corresponding simulations that by integrating a nanopore onto the FluidFM, nanoscale features could be successfully imaged, but the increased sensitivity of the probe current to sample distance comes with higher sensitivity to an inherent SICM wall artefact.
关键词： nanopore,ion current images,Scanning ion conductance microscopy,FluidFM,atomic force microscopy
更新于2025-09-23 15:21:21
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On the quantum-mechanics of a single photon
摘要： It is shown that a Dirac(-type) equation for a rank-two bi-spinor field ψph on Minkowski (configuration) spacetime furnishes a Lorentz-covariant quantum-mechanical wave equation in position-space representation for a single free photon. This equation does not encounter any of the roadblocks that have obstructed previous attempts (by various authors) to formulate a quantum-mechanical photon wave equation. In particular, it implies that the photon wave function ψph yields conserved non-negative Born-rule-type quantum probabilities and that its probability current density four-vector transforms properly under Lorentz transformations. Moreover, the eigenvalues of the pertinent photon Dirac Hamiltonian and the vector eigenvalues of the photon momentum operator yield the familiar Einstein relations E = ?ω and p = ?k, respectively. Furthermore, these spin-1 wave modes are automatically transversal without the need of an additional constraint on the initial data. Some comments on other proposals to set up a photon wave equation are supplied as well.
关键词： probability current,wave function,quantum-mechanics,photon,Dirac-type equation,Born-rule,Einstein relations,transversal modes,Lorentz-covariant
更新于2025-09-23 15:21:21