Types Of Diodes Research Articles

High-power cold diodes for the protection of a 1.5 T superconducting MRI magnet system

Cold diodes play a crucial role in various operational aspects of the superconducting magnet of magnetic resonance imaging (MRI) scanners. The forward and reverse characteristics and failure modes are studied for two types of high-power rectifier diode to find their suitability for application at 4.2 K in a whole-body 1.5 T superconducting MRI magnet system. The diodes are characterized at various temperatures (300 K, 77 K and 4.2 K) in the current range up to 600 A. The turn-on voltage of the diodes at 4.2 K is found to be increased by 7–12 times that of room temperature. The diodes show negative differential resistance (NDR) beyond 1 A of forward current at 4.2 K. The forward voltage stabilizes in the range of 1.22–1.24 V after attaining the turn-on voltage in the range of 5–8 V. The significance of NDR is analysed for the MRI magnet. The long-term stability of the forward voltage is studied at 77 K with 550 A of forward current. Two modes of diode failure are also studied to foresee any failure during the operation of the magnet.

PEMBUKTIAN LASER DIODA SPEKTRUM BIRU 1500 miliWatt DIGUNAKAN SEBAGAI KOMPONEN PEMANCAR CAHAYA PADA OPTICAL WIRELESS TRANSFER ENERGY

So far, the transfer of electric power is done by wire or cable. Recent discoveries use electromagnetic waves or magnetic induction. In this study, we tried the latest innovations, namely trials to prove with light as a substitute for wire media. The light (beam) used is a laser beam. The use of a diode type laser optical component with a blue color in the technology for wireless transfer of electrical energy. Laser tested 1500 milliWatt power. The working voltage is 6 Volts, 1 ampere. While the measurement of voltage, current and light strength with a multimeter fluxmeter. The electrical load used for this experiment is a red LED (Light Emiting Diode), with an additional 220 ohm resistor, 0.5 watts.This research method uses the type of experiment (experiment).The variables tested and measured are voltage in volts, current in amperes and light intensity in lux. The power supply can be varied from 0 volts to 15 volts, the current is 1.5 amperes of direct current. Light measuring instrument (fluxmeter or lightmeter) is expressed in lux.The results of the tests and measurements are expressed in the form of a graph of the current voltage and light intensity in the form of a graph. At a distance of 3 meters with a source voltage of 6 volts and 1 ampere on the laser, the electrical energy generated is transferred is an electric voltage of 3.9 volts, an electric current of 8.75 milli-Amperes.From this experiment, it can be proven that light can be used as a medium to distribute or transfer electrical energy, from one place to another, which is called optical wireless energy transfer. The transfer of electric power can be done with light.Keywords: Optical Wireless Energy Transfer, Blue Laser-Diode, Lux.

Sustainable power generation for at least one month from ambient humidity using unique nanofluidic diode

The continuous energy-harvesting in moisture environment is attractive for the development of clean energy source. Controlling the transport of ionized mobile charge in intelligent nanoporous membrane systems is a promising strategy to develop the moisture-enabled electric generator. However, existing designs still suffer from low output power density. Moreover, these devices can only produce short-term (mostly a few seconds or a few hours, rarely for a few days) voltage and current output in the ambient environment. Here, we show an ionic diode–type hybrid membrane capable of continuously generating energy in the ambient environment. The built-in electric field of the nanofluidic diode-type PN junction helps the selective ions separation and the steady-state one-way ion charge transfer. This directional ion migration is further converted to electron transportation at the surface of electrodes via oxidation-reduction reaction and charge adsorption, thus resulting in a continuous voltage and current with high energy conversion efficiency.

High-performance self-driven ultraviolet photodetector based on SnO2 p-n homojunction

Taking advantage of the high-quality p-type epitaxial SnO2:Mg film achieved in our previous study, a p-SnO2:Mg/n-SnO2 homojunction based ultraviolet photodetector was fabricated on a c-sapphire substrate by pulsed laser deposition in this work. The p-SnO2:Mg/n-SnO2 homojunction exhibits a typical diode behavior, with a rectifying ratio approaching 201 at 2 V and −2 V. Compared with the traditional metal-semiconductor-metal SnO2-based ultraviolet photodetector, the present p-n homojunction based photodetector is self-powered under 0 V bias. The built-in electric field in the interface depletion region of the p-SnO2:Mg/n-SnO2 homojunction separates photogenerated electron-hole pairs rapidly, which renders the photodetector an ultra-fast response speed (τr = 0.57 ms, τd = 0.64 ms). In addition, the detector exhibits a maximum photocurrent Ip of 1.5 nA under illumination with 290 nm light at 1.177 mW/cm2. At the same time, it shows a higher responsivity of 1.55 mA/W, and a higher detectivity of 9.8 × 1010 Jones, than traditional detectors. These results imply great application potential of SnO2 homojunction for UV photodetectors as well as other power devices.

A Power Quality Improved EV Charger by Using Bridgeless CUK Converter

Abstract: This study designs and develops an improved bridgeless (BL) Cuk converter-based electric vehicle (EV) battery charger with a high-power factor and higher efficiency. It offers a low-cost, high-power-density-based charging solution for EVs. This charger has fewer components functioning during a single switching cycle, which decreases the extra conduction loss experienced by the typical charger's diode bridge rectifier. As a result, it boosts the charger's efficiency. The suggested topology also avoids the undesired capacitive coupling loop and unwanted conduction via the body diode of the inactive switch in the previously developed BL Cuk converter. This considerably enhances the charger's efficiency. A flyback converter synchronises the orders for constant current and constant voltage charging. The suggested charger draws a sinusoidal current from an alternating current main, and the overall harmonic distortion in the supply current is kept within the IEC 61000-3-2 requirements. The suggested charger's increased efficiency and power quality indices are studied to verify its good charging performance under all operational situations. Keywords: Bridgeless (BL) Cuk converter, discontinuous conduction mode (DCM), flyback converter, power factor correction (PFC), and power quality are all terms used to describe a battery charger (PQ).

High-performance silicon PIN diode switches in the 2-µm wave band.

The 2-µm wave band has attracted significant research interest due to its potential applications for next-generation high-capacity optical communication and sensing. As the key component, fast optical switches are essential for an advanced and reconfigurable optical network. Motivated by this prospect, we propose and demonstrate two typical silicon PIN diode switches at 2 µm. One is based on a coupled microring resonator (CMRR), and the other is based on a Mach-Zehnder interferometer (MZI) with a push-pull-like configuration. The measured insertion loss of the CMRR switch is <2.5 dB, and the cross talk is <-10.8 dB. The insertion loss of the MZI switch is <2 dB, and the cross talk is <-15.6 dB. The switch times of these two structures are both lower than 12.5 ns.

Asymmetric Nanochannel Network-Based Bipolar Ionic Diode for Enhanced Heavy Metal Ion Detection

A higher rectification degree in ionic diodes is required to achieve better performance in applications. Nonetheless, the active geometrical change that is critical for inducing electrical potential asymmetry is difficult to realize in typical ionic diodes because of the intrinsic limitation of the fabrication method. Here, we propose a nanochannel-network-based bipolar diode with a high rectification degree of ∼1600─the highest value realized until now, to the best of our knowledge. Such a high rectification is obtained based on the synergetic effect of the bipolar surface charge and the optimization of the microchannel through experimental studies and multiphysics numerical simulations. It induces ion concentrations at the heterogeneous junction based on the accumulation effect under the forward potential bias. In particular, this proposed molecular concentration occurs in the ohmic region without vortex and instability that is inevitable at the conventional nano-electrokinetic concentration. Combining this accumulation with the horizontally aligned configuration of the nanochannel network membrane (NCNM), a highly sensitive and quantitative mercury ion (Hg2+) sensor based on a fluorescent signal is fabricated that allows direct measurement using a general fluorescent microscope. The detection limit of Hg2+ is 10 pM, which is ∼10 times lower than the best detection limit realized so far (∼100 pM) in fluorescent dye-based detection. This demonstrates the potential of asymmetric NCNM for high-performance ion transport in applications such as energy conversion, based on its design and material flexibility.

Impact of Laser‐Induced Graphitization on Diamond Schottky Barrier Diodes

Pseudovertical Schottky barrier diodes (SBDs) are fabricated on a single‐crystal diamond substrate. Herein, the structural and electrical influence of laser‐induced graphitization which takes place during the laser‐dicing process is investigated. Before laser irradiation, the fabricated SBDs show a high rectifying ratio of more than 11 orders at ±10 V and undetectable leakage current. Ideality factor (n) and Schottky barrier height (ϕ b) are estimated to be 1.09 and 1.35 eV, respectively. After laser irradiation, the SBDs still exhibit good diode behavior, in which n and ϕ b values slightly change by 10%. Leakage current is increased about two orders of magnitude and breakdown voltage is degraded from 940 to 375 V due to the presence of graphite debris. After removing the graphite debris utilizing the oxygen plasma cleaning process through an inductively coupled plasma (ICP) system, all SBDs are recovered back to typical diode characteristics. It is found that strain and surface defects that may be introduced during laser dicing and post‐ICP etching do not severely influence SBD characteristics.

An Investigation on Hybrid Particle Swarm Optimization Algorithms for Parameter Optimization of PV Cells

The demands for renewable energy generation are progressively expanding because of environmental safety concerns. Renewable energy is power generated from sources that are constantly replenished. Solar energy is an important renewable energy source and clean energy initiative. Photovoltaic (PV) cells or modules are employed to harvest solar energy, but the accurate modeling of PV cells is confounded by nonlinearity, the presence of huge obscure model parameters, and the nonattendance of a novel strategy. The efficient modeling of PV cells and accurate parameter estimation is becoming more significant for the scientific community. Metaheuristic algorithms are successfully applied for the parameter valuation of PV systems. Particle swarm optimization (PSO) is a metaheuristic algorithm inspired by animal behavior. PSO and derivative algorithms are efficient methods to tackle different optimization issues. Hybrid PSO algorithms were developed to improve the performance of basic ones. This review presents a comprehensive investigation of hybrid PSO algorithms for the parameter assessment of PV cells. This paper presents how much work is conducted in this field, and how much work can additionally be performed to improve this strategy and create more ideal arrangements of an issue. Algorithms are compared on the basis of the used objective function, type of diode model, irradiation conditions, and types of panels. More importantly, the qualitative analysis of algorithms is performed on the basis of computational time, computational complexity, convergence rate, search technique, merits, and demerits.

Forward Beam Monitor for the KATRIN experiment

The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to measure the neutrino mass with a sensitivity of 0.2 eV (90 % CL). This will be achieved by a precision measurement of the endpoint region of the β-electron spectrum of tritium decay. The β-electrons are produced in the Windowless Gaseous Tritium Source (WGTS) and guided magnetically through the beamline. In order to accurately extract the neutrino mass the source activity is required to be stable and known to a high precision. The WGTS therefore undergoes constant extensive monitoring from several measurement systems. The Forward Beam Monitor (FBM) is one such monitoring system. The FBM system comprises a complex mechanical setup capable of inserting a detector board into the KATRIN beamline with a positioning precision of better than 0.3 mm. The electron flux density at that position is on the order of 106 s-1 mm-2. The detector board contains two silicon detector chips of p-i-n diode type which can measure the β-electron flux from the source with a precision of 0.1 % within 60 s with an energy resolution of FWHM = 2 keV. The unique challenge in developing the FBM arises from its designated operating environment inside the Cryogenic Pumping Section which is a potentially tritium contaminated ultra-high vacuum chamber at cryogenic temperatures in the presence of a 1 T strong magnetic field. Each of these parameters do strongly limit the choice of possible materials which e.g. caused difficulties in detector noise reduction, heat dissipation and lubrication. In order to completely remove the FBM from the beam tube a 2 m long traveling distance into the beamline is needed demanding a robust as well as highly precise moving mechanism.

Plasmonic Tunnel Diode and Photodetector based on Layer‐Stacked AuNP‐Nanomembrane/p‐Si Heterojunction

AbstractElectronic devices with rectifying effect are typical building blocks for integrated circuits and useful for photodetectors. Herein, a new type of diode based on plasmonic tunnel hetero‐nanostructure is reported. By constructing a planar plasmoelectric junction between p‐Si and Au pad electrode with a few‐layer‐stacked 2D plasmonic AuNP‐nanomembrane as a medium layer, rectifying behavior of the device is achieved, though the direct contact between bulk Au and semiconductor usually tends to form ohmic contact. The electrically driven plasmons enable the 2D AuNP‐nanomembrane to be electron‐rich, while the asymmetric band alignment which causes bidirectionally different barrier at the (buried) interface results in the unidirectional rectifying behavior of the constructed plasmonic diode (p‐diode). The planar junction made of shell‐isolated Au@SiO2 NP‐nanomembrane (instead of AuNP‐nanomembrane) shows still rectifying behaviors but better photoresponse, due to structurally well‐defined/ordered nanostructures and intensified plasmonic tunneling effect of the nanomembrane. The as‐constructed p‐diode‐based photodetector with Au@SiO2 NP‐nanomembrane shows impressive photoresponse with a high photoresponsivity value of 6.496 A W‐1 and a detectivity value of 1.9859 × 1011 Jones under the 268 µW cm‐2 650 nm laser irradiance, comparable to the reported values of similar devices prepared from other 2D materials.

Characterization of self-magnetic pinch radiographic diode performance on RITS-6 at Sandia National Laboratories. II. Coupling between the inductive voltage adder and the SMP load

The self-magnetic pinch (SMP) diode is a type of radiographic diode used to generate an intense electron beam for radiographic applications. At Sandia National Laboratories, SMP was the diode load for the six-cavity radiographic integrated test stand inductive voltage adder (IVA) driver operated in a magnetically insulated transmission line (MITL). The MITL contributes a flow current in addition to the current generated within the diode itself. Extensive experiments with a MITL of 40 Ω load impedance [T. J. Renk et al., Phys. Plasmas 29, 023105 (2022)] indicate that the additional flow current leads to results similar to what might be expected from a conventional high-voltage interface driver, where flow current is not present. However, when the MITL flow impedance was increased to 80 Ω, qualitatively different diode behavior was observed. This includes large retrapping waves suggestive of an initial coupling to low impedance as well as diode current decreasing with time even as the total current does not. A key observation is that the driver generates total current (flow + diode) consistent with the flow impedance of the MITL used. The case is made in this paper that the 80 Ω MITL experiments detailed here can only be understood when the IVA-MITL-SMP diode is considered as a total system. The constraint of fixed total current plus the relatively high flow impedance limits the ability of the diode (whether SMP or other type) to act as an independent load. An unexpected new result is that in tracking the behavior of the electron strike angle on the converter as a function of time, we observed that the conventional cIVx “Radiographic” radiation scaling (where x ∼ 2.2) begins to break down for voltages above 8 MV, and cubic scaling is required to recover accurate angle tracking.

Design and Simulation Investigations of Stagger-Tuned W-Band Gyro-Twystron

In the present article, a multi-cavity W-band gyro-twystron amplifier operating in fundamental TE₀₁ mode has been designed, investigated for its beam-wave interaction behavior, and its performance has been enhanced by optimizing a diode type electron gun with a nominal velocity spread and stagger-tuning technique. The particle-in-cell simulation of the present gyro-twystron has predicted a peak RF output power of &#x007E;84 kW with a saturated gain of &#x007E;37 dB. The use of staggered RF cavities improved the bandwidth up to 1.5 GHz, which was found to be 2.5 times more than the synchronously tuned W-band gyro-twystron. The power conversion efficiency of the present stagger-tuned amplifier has been calculated as &#x007E;22&#x0025;. A single anode magnetron injection gun has been designed and modeled to form the gyrating electron beam with 65 kV, 6 A, and 4&#x0025; velocity spread by using 2-D electron optics code. A collector with an effective collecting area and an output window have been designed and studied to extract the remaining energy of spent electrons and collect the RF power from the vacuum environment, respectively.

Solar Photovoltaic System-Based Reduced Switch Multilevel Inverter for Improved Power Quality

This paper deals with a reduced switch multi-level inverter for the solar photovoltaic system-based 127-level multi-level inverter. The proposed technique uses the minimum number of switches to achieve the maximum steps in staircase AC output voltage when compared to the flying capacitor multi-level inverter, cascaded type multilevel inverter and diode clamped multi-level inverter. The use of a minimum number of switches decreases the cost of the system. To eliminate the switching losses, in this topology a square wave switch is used instead of pulse width modulation. Thereby the total harmonic distortion (THD) and harmonics have been reduced in the pulsating AC output voltage waveform. The performance of 127-level MLI is compared with 15 level, 31-level and 63-level multilevel inverters. The outcomes of the solar photovoltaic system-based 127-level multi-level inverter have been simulated in a MATLAB R2009b environment.

Miniature optical force levitation system

Optical levitation technology is a new levitation technology for trapping micro/nano-particles. By taking advantage of the mechanical effect of light, it has the characteristics of non-contact and high sensitivity. However, the traditional optical levitation system is large in volume, complex in adjustment, and greatly affected by the external environment. Herein, a miniature optical levitation system based on a laser diode, miniature lenses, and a micro-electro-mechanical system (MEMS) particles cavity is proposed. First, we analyze the output spot characteristics of the laser diode. Being compared the characteristics of different kinds of laser diodes, the type, wavelength, and power of diodes in the levitation system are determined. Then, the micro-particles cavity is fabricated based on the MEMS process. The MEMS process is widely used in the manufacturing of micro-electronic devices because of its advantages of small size, high precision, and easy mass production. The particle cavity processed in this way can not only ensure the advantage of small volume, but also possesses high processing repeatability. The volume of the entire package including the light source, focusing lenses, and MEMS cavity is just Φ 10 mm×33 mm, which is the smallest optical levitation system reported, to the best of our knowledge. After the entire levitation system is designed and set up, one silica particle of 10 µm diameter is stably trapped in the atmospheric environment. Finally, the micro-displacement and vibration signal are detected by a four-quadrant photoelectric detector to evaluate the stiffness of the optical levitation system.

Effects of Violet-Blue Light-Emitting Diode on Controlling Bacterial Contamination in Boiled Young Sardine.

The aim of this study was to evaluate bacterial decontamination of boiled young sardine by treatment with violet-blue light followed by cooling storage of the irradiated boiled sardine. Viable cell count in the samples was evaluated after irradiation with four types of violet-blue light-emitting diodes (LEDs; peak wavelength at 405, 412, 421 or 455 nm) and subsequent cooling storage for two days. LED (405 nm) exhibited bactericidal and growth suppression effects. The irradiation gave a 47% bactericidal rate in comparison with no irradiation samples (control) and the two-day storage suppressed the increase in cell counts to 24%, while the rate of increase was 545% for the control. Integrated viability (IV) based on growth delay analysis was estimated after irradiation of four isolates from boiled sardine with 405 nm light. The irradiation caused growth delay against all isolates, resulting in smaller IV values for three isolates compared to those viabilities estimated from colony forming units. Exposure (405 nm) at 432 J/cm2 fluence resulted in a decrease in water content, resulting in an increase in salinity of the samples. This study demonstrated the advantages of light emitting a narrow violet region as a non-thermal disinfection technology in the processing and storage of boiled sardines.

Effect of wall roughness on the hydrodynamic cavitation phenomena in a circular venturi using RANS numerical simulations

Hydrodynamic cavitation is the recent advanced oxidation technique that finds applications in wastewater treatment, nanoparticle synthesis, mineral processing, sterilization, chemical synthesis. Owing to such overwhelming industrial applications, it has received a considerable attention in the recent past. Venturi and orifice geometries are linear flow devices for hydrodynamic cavitation, whilst vortex diode type geometries are often terms as rotating flow devices. In this work, RANS numerical simulations were conducted in a venturi over a wide range of geometrical parameters, such as 10°≤α≤30° (Half convergent angle), 4°≤β≤12° (Half divergent angle), 0≤L/d≤2(Throat length to throat diameter ratio). The pressure inlet condition is employed with a pressure drop of 400 kPa and wall roughness height (KS) of 1 mm. Cavitation phenomenon is explained in detail by presenting numerical results on vapor volume fraction contours, pressure, velocity and turbulent kinetic energy profile along venturi axis length. All else being equal, the numerical simulations revealed that the inclusion of surface roughness indeed enhances the intensity of cavitation.

Ag/SeO2/C Avalanche Type Resonant Tunneling Schottky Barriers

Herein, the design and characterization of Ag/SeO2/C avalanche type resonant tunneling devices are reported. Thin pellets of SeO2 nano-powders pressed under hydraulic pressure of 1.0 MPa which is used as the active material are characterized. They showed tetragonal structure refereeing to space group of P42mbc and lattice parameters of a=b= 7.866 Å and c=5.336 Å. The current-voltage characteristic curves have shown that SeO2 can perform as active media to produce resonant tunneling diodes when forward biased and as avalanche type diode when reverse biased. The peak to valley current ratios of these diodes reached 18.3. In addition, the impedance spectroscopy measurements have shown that the device works in the low impedance mode when operated in the microwave range of frequency near 1.50 GHz. Negative conductance effect is observed in that frequency domain. The features of the Ag/SeO2/C nominate them for use as signal amplifiers and microwave oscillators.

Evidence of the Ambipolar Behavior of Mo6 Cluster Iodides in All-Inorganic Solar Cells: A New Example of Nanoarchitectonic Concept.

Ambipolar materials such as carbon nanotubes, graphene, or 2D transition metal chalcogenides are very attractive for a large range of applications, namely, light-emitting transistors, logic circuits, gas sensors, flash memories, and solar cells. In this work, it is shown that the nanoarchitectonics of inorganic Mo6 cluster-based iodides enable to form thin films exhibiting photophysical properties that enable their classification as new members of the restricted family of ambipolar materials. Thus, the electronic properties of the ternary iodide Cs2[{Mo6I8i}I6a] and those of thin films of the aqua-complex-based compound [{Mo6I8i}I4a(H2O)2a]·xH2O were investigated through an in-depth photoelectrochemical study. Once hole/electron pairs are created, the holes and electrons turn to be transported simultaneously in opposite directions, and their lifetimes exhibit similar values. The ambipolar properties were demonstrated via the integration of [{Mo6I8i}I4a(H2O)2a]·xH2O as light harvesters in an all-solid solar cell. A significant photoresponse with a typical diode characteristic clearly provides evidence of the simultaneous transfer and transport of holes and electrons within the [{Mo6I8i}I4a(H2O)2a]·xH2O layer. The ambipolar behavior results, on the one hand, from the confinement of electrons imposed by the nanometric size of the molecular metal clusters and, on the other hand, from the poor electronic interactions between clusters in the solid state. Such molecular structure-based layers lead naturally to an intrinsic semiconducting behavior.

Ефективність виробництва харчових яєць за використання для утримання несучок монохромного світла з різною довжиною світлової хвилі

Ефективність виробництва харчових яєць за використання для утримання несучок монохромного світла з різною довжиною світлової хвилі