Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Chaorong Wang, Xiaohu Fang

This work presents a novel bandpass matching network (BMN)-based switch design methodology. Theoretical analysis shows that, compared to conventional low-pass matching network (LMN)-based designs, the proposed approach enables the upward shift of the operating band while maintaining impedance matching and enhancing isolation. This makes the method particularly suitable for realizing wideband, high-frequency switches with high isolation in semiconductor technologies with limited transition frequency (<italic>f_T</italic>). To validate the concept, a seventh-order single-pole single-throw (SPST) switch was designed and fabricated using a 0.15 &#x03BC;m GaN-on-SiC process with a nominal <italic>f_T</italic> of 35 GHz. Measurement results show that the proposed switch achieves an insertion loss below 2 dB and isolation greater than 33 dB across the 15&#x2013;40 GHz band. Moreover, the design demonstrates excellent linearity, with a measured third-order input intercept power of 49-52 dBm.

Nikolas Franke, Luca Fabbri, Lorenzo Margotti et al.

ABSTRACT Charge carrier transport in disordered semiconductors is critically influenced by the shape of the band tail in the density of states (DOS). To minimize energetic disorder and suppress band tails, deposition processes and post‐treatment methods of semiconducting thin films must be carefully optimized. While capacitance–voltage (CV) measurements are routinely employed to extract doping densities and flatband voltages, no standardized procedure currently exists to quantitatively determine the DOS from such measurements. In this work, we address this gap by introducing a novel method to extract quantitative DOS information from CV data. Our approach relies on an analytical solution for charge accumulation in an exponential DOS distribution. We apply the method to Indium Gallium Zinc Oxide (IGZO) thin‐film transistors and systematically investigate how measurement frequency and channel geometry affect the results. Comparison with alternative optical and electrical techniques confirms that CV measurements can provide reliable and straightforward access to DOS parameters, provided that the transistor channel dimensions exceed L × W = 20 µm × 100 µm. Additionally, CV measurements offer practical advantages, as they are fully compatible with standard transistor architectures, including encapsulation and light shielding commonly used in technological applications.

Guillermo López‐Polín, Miriam Jaafar, Pablo Ares

ABSTRACT In our original publication, “Magnetic field screening of 2D materials revealed by magnetic force microscopy,” we demonstrated that few‐layer graphene (FLG) exhibits a measurable magnetic field screening effect of approximately 0.5% per graphene layer, as revealed by magnetic force microscopy (MFM). Here, we focus on the broader implications of this phenomenon for devices employing FLG as electrodes in van der Waals heterostructures. We highlight that the cumulative diamagnetic screening of FLG can substantially reduce the effective magnetic field experienced by the active region of a device, which must be considered for accurate quantitative interpretation of magnetic field‐dependent measurements. This Addendum clarifies how FLG's intrinsic diamagnetism can influence quantitative analyses and theoretical comparisons, while leaving the qualitative conclusions of our original study unaffected.

Harsha Ragini Aturi, Ramana Murthy Gajula, Deepshikha Rathore

Abstract The rapid development of hafnium zirconium oxide (HZO) thin films has established ferroelectric field‐effect transistors (FeFETs) as strong candidates for future non‐volatile memory and logic‐in‐memory (LiM) technologies. While earlier reviews mainly offered broad overviews, this work introduces a conceptual framework connecting deposition methods, phase stability, and device performance. This work categorizes fabrication techniques (ALD, CVD, PVD, CSD) based on their influence on phase stabilization and transformation, supported by comparative tables and schematic diagrams illustrating their impact on FeFET operation. A dedicated section discusses reliability challenges (wake‐up, fatigue, imprint, retention loss), contrasting ferroelectric capacitors (FeCAPs) with FeFETs to highlight device‐level complexities. Additionally, a comparative performance table of reported FeFET stacks summarizes key metrics such as remanent polarization, threshold voltage control, retention, and endurance. By combining thorough comparison with conceptual categorization, this review provides both a structured perspective and practical insights into integrating HZO‐based FeFETs into future computing systems.

Ke Hu, Zean Guo, Jiawei Wang et al.

Abstract Thin film transistors (TFTs) based on amorphous oxide semiconductors (AOS) are promising candidates for panel displays. However, the trade‐off between mobility and reliability in AOS‐TFTs hinders their further applications in next‐generation display techniques and newly developed logic and memory circuits. Here, a structural strategy is proposed for the mobility‐reliability trade‐off, via a triple‐layer channel containing a Ga‐free high‐mobility layer (amorphous InSnZnO, a‐ITZO) sandwiched by two Ga‐rich layers (amorphous InGaZnO, a‐IGZO) with higher reliability. Gate‐induced carrier accumulation is verified mainly being energetically confined within the high mobility a‐ITZO layer, at the newly defined a‐ITZO/a‐IGZO interface. Compared to single layer a‐ITZO‐TFTs, triple‐channel a‐IGZO/a‐ITZO/a‐IGZO TFTs (GTG‐TFTs) exhibit outstanding stability and electrical transport performances, with suppressed positive/negative‐bias‐stress voltage shifts from 1/0.3 to 0.1/0.004 V, enhanced field effect mobility from ≈40 to 56 cm2V−1s−1, and optimized sub‐threshold swing down to 80 mV dec−1. Further numerical simulations and charge transport characterizations, including magnetotransport and gate‐induced Hall effect, indicate that charge transport in tri‐layer structure is less affected by energetic disorders present at gate insulator interfaces.

Chinmoy Biswas, Nafis Faisal, Vivek Chowdhury et al.

Sparsity, defined as the presence of missing or zero values in a dataset, often poses a major challenge while operating on real-life datasets. Sparsity in features or target data of the training dataset can be handled using various interpolation methods, such as linear or polynomial interpolation, spline, moving average, or can be simply imputed. Interpolation methods usually perform well with Strict Sense Stationary (SSS) data. In this study, we show that an approximately 62\% sparse dataset with hourly load data of a power plant can be utilized for load forecasting assuming the data is Wide Sense Stationary (WSS), if augmented with Gaussian interpolation. More specifically, we perform statistical analysis on the data, and train multiple machine learning and deep learning models on the dataset. By comparing the performance of these models, we empirically demonstrate that Gaussian interpolation is a suitable option for dealing with load forecasting problems. Additionally, we demonstrate that Long Short-term Memory (LSTM)-based neural network model offers the best performance among a diverse set of classical and neural network-based models.

Junhyeon Jo, Samuel Mañas-Valero, Eugenio Coronado et al.

van der Waals magnets are emerging as a promising material platform for electric field control of magnetism, offering a pathway towards the elimination of external magnetic fields from spintronic devices. A further step is the integration of such magnets with electrical gating components which would enable nonvolatile control of magnetic states. However, this approach remains unexplored for antiferromagnets, despite their growing significance in spintronics. Here, we demonstrate nonvolatile electric field control of magnetoelectric characteristics in van der Waals antiferromagnet CrSBr. We integrate a CrSBr channel in a flash-memory architecture featuring charge trapping graphene multilayers. The electrical gate operation triggers a nonvolatile 200 % change in the antiferromagnetic state of CrSBr resistance by manipulating electron accumulation/depletion. Moreover, the nonvolatile gate modulates the metamagnetic transition field of CrSBr and the magnitude of magnetoresistance. Our findings highlight the potential of manipulating magnetic properties of antiferromagnetic semiconductors in a nonvolatile way.

Miguel Franco, Asal Kiazadeh, Rodrigo Martins et al.

Abstract Industry 4.0 is accelerating the growth of connected devices, resulting in an exponential increase in generated data. The current semiconductor technology is facing challenges in miniaturization and power consumption, demanding for more efficient computation where new materials and devices need to be implemented. One of the most promising candidates for the next technological leap is the memristor. Due to their up‐scale manufacturing, the majority of memristors employed conventional deposition techniques (physical and chemical vapor deposition), which can be highly costly. Recently, printed memristors have gained a lot of attention because of their potential for large‐scale, fast, and affordable manufacturing. They can also help to reduce material waste, which supports the transition to a more sustainable and environmentally friendly economy. This review provides a perspective on the potential of printed electronics in the fabrication of memristive devices, presenting an overview of the main printing techniques, most suitable for memristors development. Additionally, it focuses on the materials used for the switching layer by comparing its performance. Ultimately, the application of printed memristors is highlighted by showing the tremendous evolution in this field, as well as the main challenges and opportunities that printed memristors are expected to face in the following years.

Katharina Bischof, Vittorio Marangon, Michael Kasper et al.

Recently, the first sodium-ion cells have been commercialized and have become available for consumers. Given, moreover, the exciting announcements by several producers of such battery cells, it is of great interest to analyze these first commercial cells in order to understand which materials are used and how these cells are designed. Herein, two types of commercially available sodium-ion battery cells (cylindrical 1.5 Ah 18650 and 3.5 Ah 26700 cells) are investigated regarding (i) their electrode chemistry, (ii) their thermal properties upon discharge as a function of the applied C rate, (iii) the available specific energy, and (iv) their cell impedance. The data are correlated with the electrode thickness and electrode area obtained from an ex situ (ante-mortem) analysis of the 18650 cells, and discussed in comparison with the performance metrics reported for commercial lithium-ion cells. This comparison reveals that the herein studied 18650 sodium-ion cells (hard carbon⎪⎪NaxNiyFezMn1-y-zO2) provide a comparable or even higher specific energy (∼128 Wh kg−1) than that of graphite⎪⎪LiFePO4 lithium-ion cells.

Majjari Sudhakar, Koteswara Rao Anne

- Edge-based Internet of Things devices have transformed smart farming, aiding in efficient data collection and processing for optimal resource utilization and crop yields. However, task scheduling and resource allocation pose significant challenges due to the dynamic nature of agricultural environments. Our research introduces a novel framework that integrates deep reinforcement learning algorithm into an edge-enabled wireless sensor network for multi-objective optimization of the functionality of the Deep Q-Networks (DQNs). This framework extends the traditional Q-learning method to manage large state-action spaces efficiently. It employs a deep neural network to approximate the Q-value function, rather than relying on a Q-table, making it more capable of handling complex problems with high-dimensional state spaces. It forms heterogenous data clusters supports an optimal task scheduling and resource allocation policies, sustains key objectives such as minimal energy consumption, latency, efficient resource utilization, and reduced task completion time. The framework's performance is evaluated in a simulated environment mimicking real-world smart farming applications. Results confirm its superiority in enhancing performance metrics and lowering energy consumption, as opposed to traditional networks.

Shanshan Wu, Letao Yu

In order to solve the problems of long adjustment time and poor stability of the commonly used speed current variable frequency negative feedback speed control system in engineering, the author proposes an improved fish school algorithm application method in variable frequency speed control systems. A fish swarm algorithm optimized based on the arena method is applied to a variable frequency speed control system, and the optimization algorithm is applied to the speed control system to screen the PI parameters that meet the requirements of the speed control system. The simulation results show that compared with manual parameter tuning, the controller parameters optimized by the improved fish school algorithm have better control performance. In the absence of overshoot starting, the starting time was shortened by 0.21s, and the system response speed was improved. When a sudden load of 6 N m is applied, the speed drop is reduced by 3 r · min−1, and the recovery time is shortened by 0.15 s, resulting in stronger anti-interference performance of the system. Conclusion: The new algorithm shortens the control time and improves the robustness of the system.

Konstantin Root, Julian Adametz, Frank Gumbmann et al.

Reliable and convenient walk-through security scanning, which doesn&#x0027;t separate people or impede their movement, is an extremely challenging task. In this paper, a novel approach for a security check with an overhead observation and a polarimetric target decomposition is presented. The viewing angle of the scanner equals a side-looking airborne radar. However, it will be shown that the established polarimetric target decomposition methods of remote-sensing are not well suited for close-range radar imaging and need to be adapted due to the differences in the geometry of the imaging scenario. The usage of a multiple input and multiple output (MIMO) array and the shorter distance between array and target need a changed decomposition technique in order to distinguish between persons with or without worn threat objects. The differences between radar remote-sensing and close-range imaging scenarios are investigated. An optimized version of the Sato four-component polarimetric scattering decomposition is derived. The proposed close-range adjustment is applied to the model and investigated experimentally with a 4-to-12 GHz fully polarimetric MIMO imaging system. Polarimetric decomposition is carried out on defined test structures with known scattering mechanisms, as well as on mannequins and persons with different threat objects like guns or explosives. In test campaigns, promising results were achieved for a correct target decomposition in radar-based walk-through security scanning.

Pengfei Wang, Huan Yang, Jiye Li et al.

Abstract The large‐area low‐temperature processing capability and versatile characteristics of amorphous oxide semiconductor (AOS) thin‐film transistors (TFTs) are highly expected to promote the developments of next‐generation displays, 3D integrated circuit (3DIC), flexible chips, and electronics. However, the abundant native defects in AOSs engrain an inherent trade‐off between high mobility and trustworthy stability in AOS TFTs, fundamentally limiting the performance metrics and integration scale of oxide‐based electronics. To surmount this obstacle, the bilayer AOS channel is highly expected to combine the merits of diversified AOSs, while the efficiency of such an AOS “heterojunction” is debatable. This work systematically compares the TFTs based on amorphous InGaZnO (a‐IGZO), amorphous InZnO (a‐IZO), and a‐IZO/a‐IGZO bilayer. The active cation interaction between metal‐oxide semiconductors gives rise to a mixed AOS layer rather than a heterojunction channel, corresponding to moderate performance metrics. Such a spontaneous cation interdiffusion is effectively prevented using a dense metal‐oxide dielectric interlayer, aluminum oxide (AlOx). The sharpened interface effectively forms an abrupt metal‐oxide heterojunction, while the electron can still tunnel through the ultrathin AlOx to create a quantum well of 2D electron gas (2DEG). The overall performance and reliability of multilayer AOS TFT are synergistically enhanced using the proposed abrupt metal‐oxide heterojunction architecture.

K. Reddy Madhavi, Mohd Nasrun Mohd Nawi, B. Bhaskar Reddy et al.

When using a Wireless Sensor Network (WSN) for target tracking applications, optimum selection of right functioning nodes can reduce the number of active nodes and also ensuring tracking reliability requirement. Due to the limitations of the WSN's sensing range, it is crucial to create a mechanism that allows nodes to coordinate in order to follow the target reliably and with a high probability. By doing this, the network's overall energy consumption can be decreased, resulting in a longer network lifetime. Target tracking (TT) is a well observed and significant application of WSNs. In simple words, it maintains a proper trade-off between tracking quality and energy consumption. In the proposed work, Particle Filter (PF) with a machine learning technique called Support Vector Machine (SVM) based energy efficient target tracking used in WSN's. PF is considered to be the most accepted filtering algorithm in various tracking and localization problems. Simulation results show greater performance in determining the target location and maintain lower energy consumption.

Krishnan Sangeetha, K. Valarmathi, T. Kalaichelvi et al.

Diabetic Retinopathy (DR) is a micro vasculardisorder that affects the eyes and is a long term effectofDiabetesmellitus. The likelihood to develop diabetic retinopathy is directly proportional to the age and duration of the diabetes, as well as increase in the level of blood glucose level and fluctuation in blood pressure levels. A person who has diabetes has more probability to develop diabetic retinopathy. The ration of people with diabetes started to increase from 285 million in 2010 and will reach up to 439 million in the year of 2030.Out of the total number of people with Diabetic Retinopathy, approximately one-fourth of the people have vision-threatening disease. Earlier detection and classificationof Diabetic Retinopathy has to be taken much care in order to sustain a patient’s vision. The diabetic Retinopathy may be classified into various stages like Mild non-proliferative retinopathy, Moderate nonproliferative retinopathy, severe nonproliferative Retinopathy and Proliferative diabetic retinopathy. Theproblem associated with the manual detection of diabetic retinopathy is that the processing time is high, effortconsumingandrequiresanophthalmologist to examine the eye retinal fund us images. The manual analysis includes Visual Acuity testing, Tonometry and Pupil dilation. The vision lost due to Diabetic retinopathy is sometimes irreparable. Hence there is a need for earlier detection and treatment to reduce the risk of blindness.Hence there are various automated methods of diabetic retinopathy screening that have made good progress using image classification, pattern recognition, and machine learning. The input to the automated image classification model can be the color fundus photography or optical Coherence tomography images.

David Edward Bruschi

We study the generation of an electric current in an ideal conducting coil, immersed in a magnetic field, due to the occurrence of a gravitational perturbation. We show that this effect can be used to detect gravitational waves impinging on the coil as well as gravitational gradients when the coil moves in a static background gravitational field. Our work opens the way to employing induced electric signals to detect dynamical gravitational fields and for gradiometry.

Teruo Matsushita

Salman Rezaei

Adam J. Moulé, Goktug Gonel, Tucker L. Murrey et al.

Abstract Molecular doping of conjugated polymers causes bleaching of the neutral absorbance and results in new polaron absorbance transitions in the mid and near infrared. Here, the concentration dependent changes in the spectra for a series of molecularly doped diketopyrrolopyrrole (DPP) co‐polymers with a series of ultra‐high electron affinity cyanotrimethylenecyclopropane‐based dopants is analyzed. With these strong dopants the polaron mole fraction (Θ) reaches saturation. Analysis of the full spectrum enables separation of neutral and polaron signals and quantification of the polaron mole fraction using a simple noninteracting site model. The peak ratios for both neutral and polaron peaks change systematically with increasing polaron mole fraction for all measured polymers. Analysis of the spectral changes indicates that the polaron mole fraction can be quantified to within 5%. While the total change in the absorbance spectrum with increasing polaron mole fraction is linear, the lowest energy polaron peak (P1) grows nonlinearly, which indicates increased polarization/delocalization. Molecular doping of polymers that form either H‐ or J‐aggregates shows systematically different spectral changes in the vibronic peak ratios of the neutral spectra and provides insights into the polymer configuration at undoped sites in the film.

Daniel Reiter, Hao Li, Badou Sene et al.

A broadband 77/79 GHz transmitter (TX) front-end for automotive long range radar (LRR) and short range radar (SRR) applications is presented in this paper. To achieve the best system performance one new TX architecture with two specifically designed voltage controlled oscillators (VCOs) is implemented in a 28 nm CMOS technology. Furthermore, the degradation of the VCO phase noise due to the TX integration is analyzed in detail and solutions to minimize the impacts are proposed and verified. Experimental results of a 20 GHz push-push VCO1 measured at the 77 GHz TX output show a continuous tuning range of 4.75 GHz, a coarse tuning range of 3.2 GHz and an average phase noise of &#x2212;100 dBc/Hz @ 1 MHz, while a 26 GHz VCO2 with third harmonic signal extraction achieves a continuous and coarse tuning range of 7.5 GHz and 4.2 GHz with an average phase noise of &#x2212;96 dBc/Hz @ 1 MHz at 79 GHz TX output. Moreover, a record pushing performance of <inline-formula><tex-math notation="LaTeX">$\rm {&lt;\!\pm }$</tex-math></inline-formula> 100 MHz/V at 77/79 GHz TX output has been achieved according to the authors&#x2019; best knowledge. The whole TX chip consumes about 860 mW from a single 2.1 V supply while providing more than 16 dBm output power over the whole frequency band.