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Numerical analysis of Ga gradient effects in ACIGS absorbers for high-efficiency tandem solar cells

Optical and Quantum electronics 2025年第3期57卷 1-19页

作者： Boukortt, Nour El I. Loureiro, Antonio Garcia Almutairi, Ohood A. Centro Singular de Investigación en Tecnoloxías Intelixentes University of Santiago de Compostela Santiago de Compostela Spain Department of Electronics and Information Systems Ghent University Technology Park 126 Zwijnaarde Belgium Department of Electronic and Electrical Engineering University College London LondonWC1E 6BT United Kingdom Energy Systems Program College of Engineering & Energy Abdullah Al Salem University Khaldiya Kuwait

Ag-alloyed Cu(In,Ga)Se₂ (ACIGS) is a promising material for the bottom subcell in tandem solar cell structures, offering a tunable bandgap that spans the optimal range for maximum efficiency;however, the bandgap widening of ACIGS thin films poses a significant challenge in enhancing their photocurrent. This paper investigates the impact of different grading profiles, specifically focusing on the 'hockey stick'/V-like Ga gradient–induced (GGI) profiles, on the performance of thin-film ACIGS cells. To enhance the physical understanding of these grading profiles we have used Silvaco TCAD tools to analyze how these profiles' depths, notch position, and slope affect the power conversion efficiency (PCE). The optimized ACIGS cell achieves a PCE of 25.80%, compared to 23.60% for the reference device. For the tandem configuration, we pair the optimized ACIGS bottom cell (double grading profile) with a perovskite top cell (band gap ~ 1.66 eV), achieving an overall efficiency of 30.26% under AM1.5G illumination. The obtained results highlight the critical role of Ga gradient profiles in enhancing the bottom cell's performance and stability. Additionally, we compare our results with existing studies to evaluate the broader impact of Ga compositional optimization on ACIGS-based solar cells. This work provides valuable insights into advanced grading strategies and helps us understand the physical behaviour of these high-performance tandem solar cells. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.

关键词： Silver alloys

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Development of Smart Waste Bin Segregation using Image Processing 13

Development of Smart Waste Bin Segregation using Image Proce...

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2021 IEEE 13th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment, and Management, HNICEM 2021

作者： Jimeno, Froilan N. Briz, Briely Jay A. Artiaga, Marvin Roy P. Angelia, Randy E. Limsangan, Noel B. University of Mindanao Electronics Engineering Program College of Engineering Education Davao Philippines University of Mindanao Computer Engineering Program College of Engineering Education Davao Philippines Mapua University School of Electrical Electronics and Computer Engineering Manila Philippines

ISBN: (纸本)9781665401678

In the Philippines, solid waste management is still a significant problem. Improper waste disposal causes serious health problems and environmental risks such as contamination of the water systems, floods, ground and air pollution, and diseases. Unfortunately, most people mistakenly believe that not segregating waste is acceptable. This study aims to develop and design a Smart Waste Bin Segregation using Image Processing and assist waste segregation through waste identification and segregation built on machine learning capable of navigating the one-time path set by the user. In particular, create an intelligent waste bin segregation prototype using image processing with three classifications. These classifications are the biodegradable, non-bio-degradable, and unknown intended to segregate solid waste into its respective bins and conduct accuracy tests using appropriate statistical tools. This device is designed for school use and may also be used in other establishments if more waste is trained, alleviate the waste segregation problem and help build an eco-friendlier society without compromising health and hygiene. The proponents successfully materialized the device, and function tests yielded an overall result of 97.33% accuracy. © 2021 IEEE.

关键词： Health risks

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Multi-Panel Extra-Large Scale MIMO Based Joint Activity Detection and Channel Estimation for Near-Field Massive IoT Access

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China Communications 2023年第5期20卷 232-243页

作者： Zhen Gao Hanlin Xiu Yikun Mei Anwen Liao Malong Ke Chun Hu Mohamed-Slim Alouini School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China MIIT Key Laboratory of Complex-Field Intelligent Sensing Beijing Institute of TechnologyBeijing 100081China The Advanced Technology Research Institute of Beijing Institute of Technology Jinan 250307China Yangtze Delta Region Academy of Beijing Institute of Technology(Jiaxing) Jiaxing 314019China Electrical Engineering Program Division of Physical Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwal 23955Saudi Arabia

The extra-large scale multiple-input multiple-output(XL-MIMO)for the beyond fifth/sixth generation mobile communications is a promising technology to provide Tbps data transmission and stable access ***,the extremely large antenna array aperture arouses the channel near-field effect,resulting in the deteriorated data rate and other challenges in the practice communication ***,multi-panel MIMO technology has attracted extensive attention due to its flexible configuration,low hardware cost,and wider *** combining the XL-MIMO and multi-panel array structure,we construct multi-panel XL-MIMO and apply it to massive Internet of Things(IoT)***,we model the multi-panel XL-MIMO-based near-field channels for massive IoT access scenarios,where the electromagnetic waves corresponding to different panels have different angles of arrival/departure(AoAs/AoDs).Then,by exploiting the sparsity of the near-field massive IoT access channels,we formulate a compressed sensing based joint active user detection(AUD)and channel estimation(CE)problem which is solved by AMP-EM-MMV *** simulation results exhibit the superiority of the AMP-EM-MMV based joint AUD and CE scheme over the baseline algorithms.

关键词： extra-large scale MIMO massive IoT access active user detection channel estimation multipanel approximate message passing

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Enhancing the Performance of E-Mode AlGaN/GaN HEMTs With Recessed Gates Through Low-Damage Neutral Beam Etching and Post-Metallization Annealing

IEEE Open Journal of Nanotechnology

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IEEE Open Journal of Nanotechnology 2023年 4卷 150-155页

作者： Chen, Yi-Ho Ohori, Daisuke Aslam, Muhammad Lee, Yao-Jen Li, Yiming Samukawa, Seiji National Yang Ming Chiao Tung University Parallel and Scientific Computing Laboratory Graduate Degree Program of College of Electrical and Computer Engineering Hsinchu300093 Taiwan Tohoku University Institute of Fluid Science Sendai980-8577 Japan National Yang Ming Chiao Tung University Parallel and Scientific Computing Laboratory Electrical Engineering and Computer Science International Graduate Program Hsinchu300093 Taiwan National Yang Ming Chiao Tung University Institute of Pioneer Semiconductor Innovation Hsinchu300093 Taiwan National Yang Ming Chiao Tung University Parallel and Scientific Computing Laboratory Institute of Communications Engineering Institute of Biomedical Engineering Hsinchu300093 Taiwan National Yang Ming Chiao Tung University Department of Electronics and Electrical Engineering Hsinchu300093 Taiwan National Yang Ming Chiao Tung University Institute of Communications Engineering Hsinchu300093 Taiwan

This study investigated the electrical properties of AlGaN/GaN high-electron-mobility transistors (HEMTs) with varied recess depths under the gate electrode. We demonstrated a recess depth of approximately 6 nm, which was achieved through neutral beam etching (NBE) technique with a low etch rate of 1.8 nm/min, resulting in device enhancement-mode (E-mode) behavior with threshold voltage (Vth) of 0.49 V. The effects of post-metallization annealing (PMA) on the device performance were also examined. The results revealed that PMA treatment improves the DC characteristics of the devices, including maximum drain current (IDMAX), transconductance (gm), subthreshold swing (SS), on-off ratio, and off-state leakage current, with maximum enhancement percentage of 18.3% for IDMAX, 3758% for on-off ratio, and 54.3% for SS. Moreover, this study compared the recess depths of metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with the SiN dielectric layer. The results showed that MIS-HEMTs exhibit more negative Vth values, which can be attributed to the controlled surface states achieved through passivation. © 2020 IEEE.

关键词： Etching

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A High-Time-Resolution Time-to-Digital Converter Using Coupled Ring Oscillator with Phase Averaging

A High-Time-Resolution Time-to-Digital Converter Using Coupl...

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IEEE Asia-Pacific Conference on Circuits and Systems

作者： Daiki Ogata Ryosuke Kamiya Yusuke Toyoshima Kenichi Ohhata Department of Engineering Electrical and Electronics Engineering Program Kagoshima University Kagoshima Japan

This paper proposes a high-time-resolution time to digital converter (TDC) using a coupled ring oscillator (CRO) with phase averaging. The CRO can generate short time interval multiphase clocks, and combining it with a counter enables a high-time-resolution TDC with a wide input range and relatively small circuitry. In addition, the application of phase averaging to the CRO reduces the timing error due to mismatch. A novel sampling technique is also proposed to eliminate the sampling error due to counter delay and glitches. Post-layout simulations were performed on a 10-bit TDC in 28-nm CMOS technology to evaluate the performance of the proposed TDC. The results showed that the high time resolution of 2.5 ps and low power dissipation of 15.6 m W at the sampling frequency of 350 MHz could be obtained, along with the FOM of 0.083 pJ/conv.-step.

关键词： Ring oscillators Semiconductor device modeling Time-frequency analysis Circuits and systems Delay lines CMOS technology Power dissipation

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Multi-Resonant Class-E2 DC-DC Converter based on Voltage-Controlled Oscillator

Multi-Resonant Class-E2 DC-DC Converter based on Voltage-Con...

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IEEE Kansas Power and Energy Conference

作者： Lucas Sangoi Mendonça Valmir de Oliveira Academic Department of Electronics Federal University of Technology-Paraná Curitiba Brazil Academic Department of Electronics Graduate Program in Electrical and Computer Engineering Federal University of Technology-Paraná Curitiba Brazil

ISBN: (数字)9798350372403

ISBN: (纸本)9798350372410

This paper shows the design and implementation of a multi-resonant Class-E 2 DC-DC converter based on voltage- controlled oscillator. By cascading a Class-E inverter to a Class-E rectifier, a double soft-switching converter is obtained, in which, the active switch turns-on with zero voltage switching and the diode turns-off with zero derivative voltage switching. This work relies on design equations based on normalized charts that relate the resonant frequency to the current transfer function, quality factor and peak values for the switch variables. In order to activate the switch, a circuit scheme is proposed based on a voltage-controlled oscillator connected to a low-side gate-driver. Therefore, it is not necessary to use a microcontroller neither auxiliary power sources. Experimental results are presented to show the feasibility of the proposed converter.

关键词： Q-factor Voltage-controlled oscillators Transfer functions Resonant frequency Rectifiers Switches DC-DC power converters

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Hardware Development of a Humanoid Robot Head: 'Gabot' 13

Hardware Development of a Humanoid Robot Head: 'Gabot'

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2021 IEEE 13th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment, and Management, HNICEM 2021

作者： Alagenio, Justein Jabanes, Edriane James L. Genobiagon, Cresencio P. Linsangan, Noel B. University of Mindanao Mechanical Engineering Program Davao Philippines Mapua University Scholl of Electrical Electronics And Computer Engineering Manila Philippines

ISBN: (纸本)9781665401678

The development aims to mimic the anthropomorphic specifications of a human head by using available modern equipment such as the 3D printing machine. The proponents developed mechanisms to meet the Anthropomorphic data of a human head, angle of actuation, and the angular velocity of the mouth, eyes, and neck. The proponents also tested motor torque and stress on the parts to ensure the robustness of the machine, which yields 520 N-mm and 27.74 MPa on the neck tilting, 188 N-mm and 24.74 Mpa on neck swinging, 114 N-mm, and 12.09 Mpa on the neck panning, 73 and 7.052 MPa on the Eye Tilting. The maximum angular velocity of each part is 266.33 deg/sec on neck tilting, 262.33 deg/sec on neck swinging, 314 deg/sec on neck panning, 795.66 deg/sec on eye tilting, and 785.66 deg/sec on eye panning. The Proponents used the MPU-6050 accelerometer to test for the result of this study to achieve the required data. The effectiveness of the machine is as follows;eyes, 92.43% for panning, and 93.60% for tilting, neck, 89.20% for panning, 75.66% for tilting, 75.52% for swinging, for the mouth, 81.94%. © 2021 IEEE.

关键词： Anthropomorphic robots

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Quality Improvements in the electrical Design of Typical DC-DC Electronic Power Converter for High-Voltage Applications 8

Quality Improvements in the Electrical Design of Typical DC-...

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8th International Conference on engineering and Emerging Technologies, ICEET 2022

作者： Recto, King Harold A. Escoto, Miguel T. Hernandez, Noel B. Ateneo de Manila University Department of Electronics Computer and Communications Engineering Quezon City Philippines Electrical and Electronics Engineering Institute University of the Philippines Diliman Quezon City Philippines Centro Escolar University Post-doctoral Program in Quality Management of the Graduate School Manila Philippines

ISBN: (纸本)9781665491068

The green transition has brought about a worldwide-shift to the use of renewables as alternative energy sources. Because of this, high voltage DC has been a field of interest in power electronics due to its capability in efficiently transmitting power to reach remote areas. Typical DC-DC electronic power converter design has the capability of boosting voltage level to a certain extent but not enough for high-voltage applications. Using the DMAIC Approach of the Six Sigma, quality improvements in the design was proposed to stabilize operating frequency, bring up the output voltage from 100 VDC to 4,000 VDC and provide at least 10% margin of error in the apparent power measured at the output side to offset inherent losses in the electrical design. These proposed quality improvements were sustained by designing a control circuit that would ensure the attainment of the parameters set in the Define Phase of the DMAIC Approach. The result of the study is a practical 12 VDC to 4,000 VDC boost converter design that has incorporated all the proposed quality improvements. © 2022 IEEE.

关键词： Six sigma

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Philippine Region-Based Food and Nutrition Cross-Reference Using Fine-Tuned Generative ChatBot

Philippine Region-Based Food and Nutrition Cross-Reference U...

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Communication & Computing (WCONF), World Conference on

作者： Reynaldo Ted L. Peñas Rhandley D. Cajote Artificial Intelligence Program University of the Philippines – Diliman Quezon City Philippines Electrical and Electronics Engineering Institute University of the Philippines – Diliman Quezon City Philippines

ISBN: (数字)9798350395327

ISBN: (纸本)9798350395334

This paper describes the development of a Large Language Model Chatbot for Philippine Food and Nutrition knowledge base. The objective is to associate the region or province of origin of any available food item in the country to the nutrients contained and the nutritional benefits to the human body, considering the build of the knowledge base coming from 30 web sites or sources. Three models have been used to test and evaluate the performance in accomplishing the task. In the training and fine-tuning efficiency, the Meta Llama 2 7B HF model is the most efficient when varying the training epochs from 1 through 5; but based on evaluation metrics of BERTScore, ROUGE Score and GLEU, the Meta Llama 3 7B Instruct model obtained the highest scores, and the highest acceptance score when tested on 100 pairs of question-and-answer with ground truths. Further demonstration of the chatbot revealed that the objective has been achieved in most query attempts during the testing phase of the development.

关键词： Training Measurement Large language models Computational modeling Knowledge based systems Hafnium Chatbots Nutrients Web sites Testing

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Non-Uniform Phase Synthesis for Cosecant-Squared Radiation Patterns

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Journal of Microwaves, Optoelectronics and Electromagnetic Applications 2024年第3期23卷

作者： Leao, Pedro A.B. Faria, Tcharles V.B. Moreira, Fernando J.S. Graduate Program in Electrical Engineering Federal University of Minas Gerais MG Belo Horizonte31270-901 Brazil Department of Electronics Engineering Federal University of Minas Gerais MG Belo Horizonte31270-901 Brazil

In the present work an analytical formulation to synthesize non-uniform phase distributions at cylindrical apertures is described. Assuming three distinct amplitude distributions, the respective phases are established to provide cosecant-squared radiation patterns. Non-uniform amplitude distributions are investigated and adopted to reduce sidelobe levels and unwanted ripples in the synthesized radiation patterns. Analytical results for the established amplitude and phase distributions at cylindrical apertures are presented. The radiation patterns for such distributions are obtained by aperture method analysis, successfully demonstrating the usefulness of the new analytical formulation. © 2024 SBMO/SBMag.

关键词： Omnidirectional antennas

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