High-performance Switching Research Articles

Triple Fano resonances metasurface and its extension for multi-channel ultra-narrow band absorber

Metasurface excited multiple Fano resonances has become a hot spot and has been widely investigated and applied in the field of optics. A metasurface designed in this paper is composed of a silicon cuboid etched with an akin rhombus hole and deposited periodically on the silica substrate. By introducing symmetry breaking, the symmetry-protected BIC is transformed into the quasi-BIC, and triple sharp Fano resonances, corresponding to 1357 nm, 1421.7 nm, and 1588.8 nm respectively, with spectral contrasts of nearly 100 % are excited. Their maximum Q-factor can reach ∼ 3 × 104. Results of multipole decomposition show that the triple Fano resonances are dominated by magnetic dipole (MD) or electric quadrupole (EQ). Additionally, by modifying the polarization angle of the incident light, the metasurface performs excellently as a bidirectional optical switch. By adding the aluminum layer under the original structure, an ultra-narrowband absorber is created with a maximum absorption rate of ∼ 100 %. The sensing performance of the absorber is studied, yielding the maximum sensitivity of 255 nm/RIU and the maximum figure of merit (FOM) of 477 RIU−1. The proposed metasurface and its extension structure are potential to be applied in as high-performance biosensors, optical switch, and coherent thermal radiation.

High-Performance Breaking and Intelligent of Miniature Circuit Breakers.

The exploitation and utilization of clean energy such as wind and photovoltaic power plays an important role in the reduction in carbon emissions to achieve the goal of “emission peak and carbon neutral”, but such a quantity of clean energy accessing the electric system will foster the transition of the electric power system structure. The intelligentization of power equipment will be an inevitable trend of development. High breaking performance, remote control and a digital detection platform of miniature circuit breaker, a protective equipment of a power distribution system, have also been inevitable requirements of the power Iot system. Based on the above, this paper studies three aspects: high-performance AC and DC general switching technology, remote control technology and operation status’ digital monitoring. A new DC non-polar breaking technology is proposed, which improves the short circuit breaking ability. An experimental prototype using the above techniques was fabricated and passed the DC 1000 V/10 kA short-circuit breaking test. On the basis of the above, an intelligent circuit breaker is developed, which contains multiple functions: remote switching, real-time temperature detection, energy metering and fault warning. Moreover, a software for digital condition monitoring and remote control is developed. This work has certain theoretical and practical significance for the development of the power Internet of things.

New Products

Pickering has added two new matrix modules to their line of PXI/PXIe instruments. The 40-724-021-L (PXI) and 42-724-021-L (PXIe) are 32x8 RF matrix modules with y-axis loop-thru and are suitable for switching frequencies up to 150 MHz. Having a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$50\Omega$</tex> characteristic impedance and front panel SMB connectors, these modules provide a simple and scalable bidirectional matrix for RF and are intended for the easy construction of high performance switching systems.

Low-Power Memristor Based on Two-Dimensional Materials.

The memristor is an excellent candidate for nonvolatile memory and neuromorphic computing. Recently, two-dimensional (2D) materials have been developed for use in memristors with high-performance resistive switching characteristics, such as high on/off ratios, low SET/RESET voltages, good retention and endurance, fast switching speed, and low power and energy consumption. Low-power memristors are highly desired for recent fast-speed and energy-efficient artificial neuromorphic networks. This Perspective focuses on the recent progress of low-power memristors based on 2D materials, providing a condensed overview of relevant developments in memristive performance, physical mechanism, material modification, and device assembly as well as potential applications. The detailed research status of memristors has been reviewed based on different 2D materials from insulating hexagonal boron nitride, semiconducting transition metal dichalcogenides, to some newly developed 2D materials. Furthermore, a brief summary introducing the perspectives and challenges is included, with the aim of providing an insightful guide for this research field.

In situ micromechanical analysis of a nano-crystalline W-Cu composite

W-Cu composites are commonly used as heat-sinks or high-performance switches in power electronics. To enhance their mechanical properties and mutually their usability, grain refinement of the initially coarse-grained microstructure was realized using high–pressure torsion. This leads to different microstructural conditions, exhibiting fine-, ultrafine-grained or nanocrystalline microstructures. Scanning as well as transmission electron microscopy was performed to analyze the respective grain size and microstructures. The hardness and Young’s modulus of the deformed specimens were quantified by nanoindentation testing. Furthermore, X–ray diffraction indicated a decreased grain size and changed lattice spacings upon increasing the deformation ratio. The deformed specimens were tested for their fracture behaviour by continuous stiffness measurements during in-situ microcantilever bending experiments. Here, mean J–integral values of 288 ± 38 J/m2 and 402 ± 89 J/m2 were determined for the 5 and 50 times turned specimens, respectively. The combination of different characterization methods applied on a W–Cu composite allows to identify both, beneficial and unfavourable microstructural components regarding the fracture properties.

First-principles investigation of amorphous Ge-Sb-Se-Te optical phase-change materials

Chalcogenide phase-change materials (PCMs) are promising candidates for nonvolatile memory and neuromorphic computing devices. The recently developed Ge2Sb2Se4Te1 alloy shows superior properties in terms of low optical loss and higher thermal stability with respect to the flagship Ge2Sb2Te5 alloy, making this new quaternary alloy a suitable candidate for high-performance optical switches and modulators. In this work, we carry out ab initio calculations to understand how selenium substitution modifies the local structure and the optical response of the amorphous quaternary alloys. We consider four amorphous Ge2Sb2Se x Te5-x (GSST) alloys with x = 1 to 4 and show that the substitution of selenium content induces a gradual reduction in the calculated refractive indices, which is in agreement with experimental observation. This improvement on optical loss stems from the increased band gap size, which is attributed to the larger Peierls-like distortion and the stronger charge transfer in the Se-richer amorphous GSST alloys.

Tunable bilayer dielectric metasurface via stacking magnetic mirrors.

Functional tunability, environmental adaptability, and easy fabrication are highly desired properties in metasurfaces. Here we provide a tunable bilayer metasurface composed of two stacked identical dielectric magnetic mirrors. The magnetic mirrors are excited by the interaction between the interference of multipoles of each cylinder and the lattice resonance of the periodic array, which exhibits nonlocal electric field enhancement near the interface and high reflection. We achieve the reversible conversion between high reflection and high transmission by manipulating the interlayer coupling near the interface between the two magnetic mirrors. Controlling the interlayer spacing leads to the controllable interlayer coupling and scattering of meta-atom. The magnetic mirror effect boosts the interlayer coupling when the interlayer spacing is small. Furthermore, the high transmission of the bilayer metasurface has good robustness due to the meta-atom with interlayer coupling can maintain scattering suppression against positional perturbation. This work provides a straightforward method to design tunable metasurface and sheds new light on high-performance optical switches applied in communication and sensing.

Photocatalysis‐Induced Nanopores toward Highly Reliable Organic Electrochemical Metallization Memory

AbstractOrganic electrochemical metallization (ECM) memory that possesses high reliable switching performance is in great demand for the future smart wearable and flexible electronics. The resistive switching (RS) behavior of organic ECM memory is determined by the micro‐morphology evolution of metal conductive filaments (CFs) during the operating process. However, the morphology controllability of CFs is generally deteriorated by their random distribution and unexpected overgrowth. Herein, a kind of nanoporous PVC/TiO2 nanocomposite is developed using photocatalytic method for improving the RS reliability of organic ECM memory. The introduction of engineered nanopores can effectively simplify the CFs morphology to obtain excellent uniformity, good retention, and low cycling degradation. In addition, taking advantage of the multilevel RS behavior and 200 × 200 memristive array artificial neural network (ANN), alphabetic data storage and image pattern recognition are successfully realized. The proposed approach is expected to provide novel platforms for the advance of highly reliable flexible electronics and ANN for intelligence applications.

Bulk Switched DC-DC Buck Converter

This paper presents a buck converter which has an high efficient and low power consumption for low power applications. The proposed topology is based on buck converter using switching MOSFET with bulk-terminal. The suitable bulk-terminal switching voltage is selected by analyzing the effect of bulk voltage on a MOSFET performance. It is concluded that the bulk-switched DC-DC buck converter structure has the advantages such as high switching performance, low power consumption and high efficiency compared to conventional DC-DC converter circuits. The efficiency value has obtained 88.2%. The proposed circuit is approved experimentally and simultaneously

Ultracompact High‐Extinction‐Ratio Nonvolatile On‐Chip Switches Based on Structured Phase Change Materials

AbstractAdopting phase change material (PCM) in constructing nonvolatile on‐chip photonic switches has received intensive attention recently. Usually, a large‐area thin PCM film is directly used to construct a switch. Here, subwavelength structured PCM supporting localized resonance are adopted to efficiently improve the switching performance in a moderate bandwidth to obtain an optimal switch of higher switching contrast, smaller footprint, lower energy consumption, and better structure stability. Such a switch consisting of three cascaded Ge2Sb2Te nanodisks with a total volume of only 0.229 µm 35 nm on top of a single mode strip silicon waveguide is demonstrated. In the experimental verification, a high extinction ratio up to 27 dB is supported by the fabricated device as a high performance switch. The proposed design methodology will find its great potential in various large‐scale integration in optical interconnection and optical computing with new architectures or applications.

E-mode All-GaN-Integrated cascode MISHEMT with GaN/InAlGaN/GaN backbarrier for high power switching performance: Simulation study

In this work, simulation-based research work based on a novel All-GaN-Integrated Cascode (AGC) MISHEMT with quaternary layer InyAlxGa1-x-yN as backbarrier has been investigated. The AGC-MISHEMT device consists of series combination of enhancement mode (recessed gate MISHEMT) and depletion-mode (MIS-gate) GaN devices with GaN/InAlGaN/GaN sandwich back barrier (SW-BB). TCAD simulations indicate that AGC-MISHEMTs with sandwich back barrier (SW-BB) exhibits simultaneous improvement in terms of drain current density (267 ​mA/mm), high ION/IOFF ratio (108), transconductance-peak (191 ​mS/mm) and breakdown voltage (371 ​V) as compared to AGC-MISHEMT with GaN buffer. The impact of varying mole fractions (x, y), thickness and position of InyAlxGa1-x-yN layer on breakdown voltage has also been examined. Improvement in drain current density up to 40% has been accomplished with increased gate oxide thickness under gate 2 (depletion-mode device) for AGC-MISHEMT with SW-BB. Besides, power switching performance has been compared for AGC-MISHEMT with SW-BB to that of AGC-MISHEMT with GaN buffer and Recessed Single Gate (RSG) MISHEMT for inductive load circuit. Significant reduction in power switching losses (i.e. 43% during turn-ON time and 87% during turn-OFF time) has been observed for AGC-MISHEMT with SW-BB as compared to RSG-MISHEMT. In addition, introduction of quaternary InAlGaN layer in backbarrier for AGC-MISHEMT also results in considerable degradation (∼89%) in power loss when input gate is in OFF-state due to improved ION/IOFF ratio in contrast with recessed single gate device.

Numerical study of a novel GaN vertical FinFET with a p-base structure for high switching performance

Numerical study of a novel GaN vertical FinFET with a p-base structure for high switching performance

High-performance electro-optical switch using an anisotropic graphene-based one-dimensional photonic crystal.

A novel electro-optical switch is proposed and investigated using the transfer matrix method (TMM) and three-dimensional finite-difference time-domain (3D FDTD) analysis at the near-infrared range. The structure is made of a defect at the middle of a one-dimensional photonic crystal. The defect consists of two anisotropic graphene (AG) sheets separated by a dielectric layer. As a result, a sharp transmission peak with a high quality factor of 5000 appears at the wavelength of 1552.4 nm where light is trapped by the defect. When an external voltage is applied across the AG sheets, their chemical potentials shift in such a way that the trapped photons are absorbed and the switch changes to ON state. According to the presented results, a high extinction ratio of 14.26 dB with a very low insertion loss of 0.18 dB are obtained. The required switching voltage and energy consumption are as low as 4.68 V and 226 fJ/bit, respectively. The 3 dB bandwidth is also calculated to be as high as 17.5 GHz, which makes our proposed switch promising for high speed optical systems.

A high-performance brain switch based on code-modulated visual evoked potentials

Objective. Asynchronous brain-computer interfaces (BCIs) are more practical and natural compared to synchronous BCIs. A brain switch is a standard asynchronous BCI, which can automatically detect the specified change of the brain and discriminate between the control state and the idle state. The current brain switches still face challenges on relatively long reaction time (RT) and high false positive rate (FPR). Approach. In this paper, an online electroencephalography-based brain switch is designed to realize a fast reaction and keep long idle time (IDLE) without false positives (FPs) using code-modulated visual evoked potentials (c-VEPs). Two stimulation paradigms were designed and compared in the experiments: multi-code concatenate modulation (concatenation mode) and single-code periodic modulation (periodic mode). Using a task-related component analysis-based detection algorithm, EEG data can be decoded into a series of code indices. Brain states can be detected by a template matching approach with a sliding window on the output series. Main results. The online experiments achieved an average RT of 1.49 s when the average IDLE for each FP was 68.57 min (1.46 × 10−2 FP min−1) or an average RT of 1.67 s without FPs. Significance. This study provides a practical c-VEP based brain switch system with both fast reaction and low FPR during idle state, which can be used in various BCI applications.

Tellurate polymorphs with high-performance nonlinear optical switch property and wide mid-IR transparency

Li2HfTeO6 has been identified to function as a mid-IR transparent NLO switch with high figures of merit.

An Effective Decoupling Control with Simple Structure for Induction Motor Drive System Considering Digital Delay

Digital processing poses a considerable time delay on controllers of induction motor (IM) driving system, which degrades the effects of torque/flux decoupling, slows the motor torque response down, or even makes the entire system unstable, especially when operating at a low switching frequency. The existing methods, such as feed-forward and feed-back decoupling methods based on the proportional integral controller (PI), have an intrinsic disadvantage in the compromise between high performance and low switching frequency. Besides, the digital delay cannot be well compensated, which may affect the system loop and bring instability. Conventional complex vector decoupling control based on an accurate IM model employs complicated decoupling loops that may be degraded by digital delay leading to discrete error. This article aims to give an alternative complex vector decoupling solution with a simple structure, intended for optimized decoupling and improving the system dynamic performance throughout the entire operating range. The digital delay-caused impacts, including secondary coupling effect and voltage vector amplitude/phase inaccuracy, are specified. Given this, the digital delay impact is canceled accurately in advance, simplifying the entire decoupling process greatly while achieving uncompromised decoupling performance. The simulation and experimental results prove the effectiveness and feasibility of the proposed decoupling technique.

Pseudopeptidic Polymer Microsphere-Filled Liquid Crystals as High-Performance Light-Scattering Switches

We, herein, report the fabrication of light-scattering switches from polymer microsphere-filled liquid crystals (PFLCs) using pseudopeptidic bottlebrush polymers. A simple method of precipitation of a polymer using the 4-cyano-4′-pentylbiphenyl (5CB) nonsolvent is employed for the preparation of PFLC devices. For this, a series of phenylalanine (Phe)-based bottlebrush polymers having different chain lengths are synthesized by ring-opening metathesis polymerization (ROMP) using the Grubbs second-generation ruthenium catalyst and used in a nematic liquid crystal (LC) matrix. The developed PFLC devices are well-characterized using various ultramicroscopic techniques such as field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and polarizing optical microscopy (POM). For the first time, the effect of the molecular weight of a polymer on electro-optic (E-O) properties of PFLC is investigated. PFLCs show significant differences in microsphere size, required operating voltage, transmittance, contrast ratio (CR ratio), memory effect, and switching speed upon subtle variation of the dopant polymer units. Overall, we demonstrated that the chain length of a polymer plays a crucial role in controlling the performance of PFLC devices. The presented methodology offers promising possibilities for the fabrication of PFLC-based switchable scattering devices with improved performance for optoelectronic applications.

High-performance inline RF MEMS switch for application in 5G mobile networks

This article presents the results of the design and analysis of a radio-frequency switch made using microelectromechanical systems technology. The device is the capacitive switch with a hybrid type of contact, in which the movable electrode of the structure – the metal membrane is part of the microwave signal line of the coplanar waveguide. The switch design is characterized by a high capacitance ratio and low contact resistance. The zig-zag elastic suspension is used to reduce the value of the pull-down voltage – 2 V and the switching time ∼ 7 us. The central resonant frequency of the switch is 3.8 GHz. In this case, in the open state, the value of the insertion loss is not more than -0.2 dB and the isolation value in the close state is not less than -55 dB. The effective frequency range is the S-band, as well as the C-, X- and Ku-band, in which the isolation value is at least -30 dB. The presented inline RF MEMS switch is suitable for use in various types of ground and satellite communications, in particular for devices and systems of 5G mobile networks.

High-power switching device based on field emission mechanism fabricated using highly crystalline single-walled carbon nanotubes

Since the Great East Japan Earthquake in 2011, there has been a growing interest in energy conservation all over the world. To build a society centered on renewable energy, it is essential to obtain inexpensive and stable renewable energy, and completely eliminate energy loss in the energy utilization system for conserving energy optimally. Towards the construction of an energy-saving low-carbon society, we have utilized the field emission (FE) characteristics of highly crystalline single-walled carbon nanotubes (HC-SWCNTs), which are synthesized by arc discharge, purified, and annealed at high temperatures, to form an excellent electron emission layer with high current density and high durability. The thin films containing HC-SWCNTs exhibit electrical properties that result in almost no heat generation at high current densities (i.e., high power densities). When the thin films fabricated in this research were used in a power switching device, the FE characteristics of HC-SWCNTs as an electron source in the device were applied to switch the ampere-order currents on and off. Owing to their high crystallinity, SWCNTs exhibit potentials close to the ideal conductive characteristics, and their performance is expected to meet the requirements of high-power density, zero energy loss, and high-frequency responses, even when compared with power devices fabricated using semiconductors, for example, SiC and GaN. Therefore, the purpose of this research is to establish a high-power-density and low-energy-loss thin-film formation technology and to develop a high-performance switching device.

Design of High-Performance Rram through Interfacial Engineering Toward Neuromorphic Application by Low-Temperature Plasma Selenization Process

The probabilistic formation of conducting filament (CF) in two-terminal Resistive switches affects the device functionality. The spontaneity of formation of CF is the key factor in determining the device reliability and can be controlled by functional layer dynamics near the interface. This functional layer can act as a series resistance as well as a barrier layer against the random migration of metallic ion and oxygen vacancies. Here, we propose the interfacial engineering by inserting WO3/WSe2 layer between the electrolyte and the active electrode. The proposed WO3/WSe2 layer provides fine control over diffusion of oxygen vacancy across AL2O3/WO3 interface, thus provide reliable and high performance for RRAM devices. In addition, inductively coupled plasma (ICP) process is used to change the WO3/WSe2 ratio to obtain the high-performance Resistive switch. The use of ICP process facilitates the synthesis of transition metal dichalcogenide (TMDs) through plasma selenization process at a temperature as low as 3000C. Therefore, the temperature required for TMDs synthesis is drastically reduced in comparison to conventional CVD process. The plasma synthesized WO3/ WSe2 is coupled with AL2O3 to form a hybrid structure for Resistive switching device. Compared with Pt/AL2O3/W device, the optimized Pt/Al2O3/WO3/WSe2/W hybrid structure show improvement in on/off ratio (104-105), multilevel characteristics (uniform LRS/HRS distribution) and retention (10 years). The results indicate that plasma engineered interface engineering can be a promising approach for improved and high-performance RRAMs.