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Overcoming solar-blind limitations: 3dEG-induced Fermi-level control in AlGaN phototransistors enables 107 out-of-band rejection and 650-photons/s detection

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Optics Express 2025年第12期33卷 24937-24948页

作者： Zhuoya Peng Jiabing Lu Zesheng Lv Hao Jiang School of Electronics and Information Technology Sun Yat-sen University Guangzhou 510006 China State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen University Guangzhou 510006 China Guangdong Engineering Technology R&D Center of Compound Semiconductors and Devices Sun Yat-sen University Guangzhou 510006 China

Solar-blind ultraviolet (SBUV) photodetectors are critical for applications requiring immunity to solar background noise, such as flame sensing and corona discharge detection. Among these, AlGaN-based heterojunction field-effect phototransistors (HFEPTs) stand out for their high sensitivity enabled by high-conductivity two-dimensional electron gas (2dEG) channels. However, conventional HFEPTs suffer from severe out-of-band photoresponse and persistent photoconductivity (PPC) decay due to deep-level heterojunction defects, limiting their practical utility in sunlight-rich environments. To address this, we propose a 3dEG-engineered AlGaN phototransistor that leverages a composition-graded channel to modulate the Fermi level. This design achieves an unprecedented spectral rejection ratio of 10 7 (260/400 nm)—surpassing 2dEG-based devices by five orders of magnitude—while maintaining sub-fW sensitivity (0.6 fW/cm 2 , equivalent to 650 photons/s). Band structure analysis reveals that the Fermi-level pinning mechanism prevents deep-acceptor-level transitions under both dark and illuminated conditions, effectively suppressing the parasitic out-of-band response and accelerating PPC decay by six orders of magnitude within 10 s. With a specific detectivity ( d *) of 5.1×10 17 Jones, the 3dEG-PT advances accurate solar-blind operation by detecting weak UV signals under solar irradiation. Our Fermi-level engineering strategy mitigates deep-level impacts, offering a scalable approach for UV photodetectors requiring high background rejection.

关键词： Aluminum gallium nitride Chemical vapor deposition Photoconductivity Photodetectors Spectral discrimination Ultraviolet light emitting diodes

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research on construction and operation parameters of an underground oil storage in depleted salt caverns in the east of China 82

Research on construction and operation parameters of an unde...

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SPE Europec featured at 82nd EAGE Conference and Exhibition, EUrO 2021

作者： Jin, Fu Xi, Wang Mingming, ding Guobin, Yang Shunyuan, Zhang Bingshan, Liu Chen, Chen CNPC Engineering Technology R&D Company Ltd. China China National Oil and Gas Exploration and Development Company Ltd. China

ISBN: (纸本)9781613997918

The crude oil price has been keeping at a low level in recent years, which made China's government put more efforts in the development of underground oil storages in depleted salt caverns. Under the initiative of "the Belt and road", a more concrete concept which is "the Silk road Economic Belt and the 21st-Century Maritime Silk road"successfully connects Jiangsu Province in the east of China. Consisting of 20 depleted caverns, Huai'an project that is still under planning is one of the most successful examples that turn depleted salt caverns into underground crude oil storages in China. Each cavern takes up 24×104m3, while the project totally takes up 480×104m3. TdMA algorithm was adopted to solve the heat exchange model of oil, brine and surrounding rocks, revealing the relationship between temperature and cavern pressure. Salt rock safety factor, salt cavern shrinkage ratio, axial stress and ground subsidence were taken into consideration to establish a 3- dimension salt rock creep model for 19 depleted salt caverns, so that the caverns' shapes were optimized. Hydrodynamics models were used to determine the oil's flow rate into and out of a 1000m deep cavern whose thermal field was simulated by software to reveal the temperature limit of oil and brine. due to geothermal gradient and continuous heat transmission, the average temperature of oil and brine goes up from 35°C to 44.3°C within 7 years, while the inner pressure goes up from 12.96MPa to 21.93MPa in a depleted salt cavern. Salt creep ratio decreases as oil is stored in underground caverns for a longer period. Salt is hardly penetrated by oil, while the temperature change has a strong influence on caverns' internal pressure. The thermal expansion factor and compressibility coefficient of crude oil and brine are both crucial to the temperature's effect on internal pressure. Caverns that have larger segments in their uppermiddle or middle parts are more stable and resistant to salt creep than those that have l

关键词： Crude oil

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Investigation on cutting fluid use in finish milling of polylactide (PLA) 3d-printed parts 20

Investigation on cutting fluid use in finish milling of poly...

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20th CIrP Conference on Modeling of Machining Operations in Mons, CIrP CMMO 2025

作者： Lorenzoni, Margaux Spitaels, Laurent rivière-Lorphèvre, Edouard Odent, Jérémy M'Saoubi, rachid Cloëz, Liam Fontaine, Michaël ducobu, François Machine Design and Production Engineering Lab Research Institute for Materials Science and Engineering University of Mons Place du Parc 20 Mons7000 Belgium University of Mons Place du Parc 20 Mons7000 Belgium R&D Material and Technology Development Seco Tools AB Björnbacksvägen 2 FagerstaSE-737 82 Sweden Department of Mechanical Engineering Sciences Division of Production and Materials Engineering Lund University Ole Römers väg 1 LundSE-221 00 Sweden FEMTO-ST Institute-Applied Mechanics Dept. Université de Franche-Comté-SUPMICROTECH-CNRS Rue de l'épitaphe 24 BesançonF-25000 France

Fused Filament Fabrication (FFF) is an additive manufacturing process based on Material Extrusion (MEX) of polymeric filament. This manufacturing technology is commonly used for personalized production applications and prototyping, allowing to obtain customized parts with complex geometries at a low cost. However, this production technique has its limitations regarding dimensional accuracy and surface roughness of the final parts. To overcome these limitations, finish milling is considered to be a promising technique as it is widely used for metallic parts. Yet, the specific thermal properties of polymers such as low thermal conductivity and low melting temperature are adding a challenge in the determination of optimal cutting conditions. In this context, the use of cutting fluid could be the key to keep the material from melting during milling. Therefore, this paper proposes to compare the impact of using a compressed air flow to dry conditions on the cutting forces and the surface quality obtained on 3d-printed polylactide (PLA) parts. The qualification test of the tool-material couple standard (NF E 66-520-6) will be used as a guideline to determine the relevance of cutting fluid use for cutting conditions varying around an operating point. Moreover, simulated cutting forces using a mechanistic model will be compared to experimental data to evaluate the applicability of the model. © 2025 The Authors.

关键词： Compressed air

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Exploring deep Learning Methods for Computer Vision Applications across Multiple Sectors:Challenges and Future Trends

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 103-141页

作者： Narayanan Ganesh rajendran Shankar Miroslav Mahdal Janakiraman SenthilMurugan Jasgurpreet Singh Chohan Kanak Kalita School of Computer Science and Engineering Vellore Institute of TechnologyChennai600127India Department of Computer Science and Engineering Koneru Lakshmaiah Education FoundationVaddeswaram522502India Department of Control Systems and Instrumentation Faculty of Mechanical EngineeringVSB-Technical University of OstravaOstrava70800Czech Republic Department of Computer Science and Engineering Vel Tech High Tech Dr.Rangarajan Dr.Sakunthala Engineering CollegeChennai600062India Department of Mechanical Engineering and University Centre for Research&Development Chandigarh UniversityMohali140413India Department of Mechanical Engineering Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and TechnologyAvadi600062India

Computer vision(CV)was developed for computers and other systems to act or make recommendations based on visual inputs,such as digital photos,movies,and other *** learning(dL)methods are more successful than other traditional machine learning(ML)methods *** techniques can produce state-of-the-art results for difficult CV problems like picture categorization,object detection,and face *** this review,a structured discussion on the history,methods,and applications of dL methods to CV problems is *** sector-wise presentation of applications in this papermay be particularly useful for researchers in niche fields who have limited or introductory knowledge of dL methods and *** review will provide readers with context and examples of how these techniques can be applied to specific areas.A curated list of popular datasets and a brief description of them are also included for the benefit of readers.

关键词： Neural network machine vision classification object detection deep learning

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Atomic-scale investigation of H-trapping by fine NbC precipitates in a low C ferritic steel

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Scripta Materialia 2023年第1期234卷

作者： Samanta, Santigopal Gangavarapu, Shashidhar Jayabalan, Bhagyaraj Makineni, Surendra Kumar dutta, Monojit Singh, Shiv Brat R&D Division Tata Steel limited Jamshedpur831001 India Department of Materials Engineering Indian Institute of Science Bengaluru Bengaluru560012 India Department of Metallurgical and Materials Engineering Indian Institute of Technology Kharagpur Kharagpur721302 India

The origin of hydrogen trapping by the Nb-carbide precipitates in a ferritic steel was studied at the atomic scale with the help of HrTEM (high resolution transmission electron microscopy) and 3d-APT (atom probe tomography). A Nb-added ferritic steel was prepared in the laboratory and subjected to aging after solutionizing treatment to have fine Nb-carbide precipitates in ferrite matrix. The precipitation kinetics were simulated beforehand using TC-Prisma in Thermocalc software. A large number of nanometer-sized Nb-carbide precipitates were observed in the ferrite matrix using TEM. 3d-APT studies on the steel sample electrolytically charged with d (deuterium) showed that the d atoms are trapped more within the precipitates than at the precipitate-matrix interfaces. It has been argued that H atoms occupy the vacant lattice sites on carbon sub-lattice sites in non-stoichiometric NbC0.83. © 2023 Acta Materialia Inc.

关键词： High resolution transmission electron microscopy

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research progress on perovskite solar cells based on organic carbon electrodes

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Carbon Letters 2025年 1-28页

作者： Lin, Zhikuan Xiong, Zhen Guo, Haijun Zhang, Hairong Wang, Mengkun Xiong, Lian Chen, Xinde School of Energy Science and Engineering University of Science and Technology of China Hefei PR China Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Tianhe District Guangzhou PR China R&D Center of Xuyi Attapulgite Energy and Environmental Materials Xuyi PR China

Carbon electrodes, renowned for their excellent moisture and air stability, present a compelling alternative to unstable hole transport materials and costly metal electrodes. In carbon electrode-based perovskite solar cells (C-PSCs), organic materials play a crucial role in optimizing the surface characteristics and electrochemical performance of carbon electrodes, thereby enhancing the photoelectric conversion efficiency. By incorporating organic material additives to modulate the pore structure and surface chemistry of carbon electrodes, the processes of photon absorption and electron transport can be effectively promoted, leading to an improvement in device performance. This article comprehensively reviews the latest research progress of organic C-PSCs, covering their device structures, working principles, as well as the modification methods, advantages, and application effects of organic materials in different layers of C-PSCs. Finally, the applications of in-situ characterization and first-principles calculations in this field are briefly introduced, providing theoretical and experimental support for in-depth research. Based on the above research and analysis, optimization strategies such as enhancing charge selectivity, improving the contact between the electrode and the perovskite layer, and enhancing the quality of the perovskite layer are proposed to drive the further development of organic C-PSCs.

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Synthesis and Up-Conversion Luminescence Properties of Er-doped Caf2 Nanoparticles

SSRN

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SSrN 2024年

作者： Tian, ran Yin, Zhi-Jiang Li, Hui Yang, Ji Wang, Wen-Yuan An, Yu-Qiang Wu, Li-Jun Yang, Ze-Yuan Yang, Xing Ge, Zhen-Hua R&D Center of China Tobacco Yunnan Industrial Co. Ltd. Kunming650032 China Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming650093 China

Calcium fluoride possesses a broad band gap, enabling it to exhibit up-conversion luminescence across an extensive variety of absorption spectra. The up-conversion luminescence performance is influenced by particle size, dispersion homogeneity, and the manufacturing method. This study successfully synthesizes CaF2 nanoparticles with a consistent microstructure using a hydrothermal technique by adjusting the reaction duration and temperature. The rare elements were evaluated to attain the up-conversion luminous performance for the CaF2 samples. The up-conversion luminous performance of CaF2 materials is examined using erbium doping. The findings indicate that the incorporation of the Er element into the CaF2 lattice leads in a reduction of the bandgap. The up-conversion luminescence performance of Er-doped samples is enhanced by Er doping in the CaF2 matrix, facilitating energy transfer. The Ca0.97Er0.03F2 sample has the maximum up-conversion spectrum intensity at a power density of 52.28 W/cm2, indicating significant potential applications in laser technology, display systems, optical storage, information security, biological imaging, and medical diagnosis and treatment. © 2024, The Authors. All rights reserved.

关键词： Luminescence of inorganic solids

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Sign-tunable exchange bias effect in proton-intercalated Fe3GaTe2 nanoflakes

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Physical review B 2023年第14期107卷 L140409-L140409页

作者： Chunsheng Wang Jie Wang Wen-Qiang Xie Gaojie Zhang Hao Wu Jianhui Zhou Xiangde Zhu Wei Ning Guopeng Wang Cheng Tan Lan Wang Haifeng du Yu-Jun Zhao Haixing Chang Guolin Zheng Wen-Tong Geng Mingliang Tian School of Physics and Optoelectronic Engineering Anhui University Hefei 230601 Anhui China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences (CAS) Hefei 230031 Anhui China School of Materials Science and Engineering Hainan University Haikou 570228 China Department of Physics South China University of Technology Guangzhou 510640 China Center for Joining and Electronic Packaging State Key Laboratory of Material Processing and Die and Mold Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China Wuhan National High Magnetic Field Center and Institute for Quantum Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China School of Science RMIT University Melbourne VIC 3001 Australia Shenzhen R&D Center of Huazhong University of Science and Technology (HUST) Shenzhen 518000 China

The exchange-bias (EB) effect, usually arising in ferromagnetic (FM)-antiferromagnetic (AFM) interfaces with uniaxial magnetic anisotropy, holds high potentials in spintronic applications. Here, we report both field-cooling and zero-field cooling EB effects with a maximal EB field |HEB| reaches up to 3859 Oe in above-room-temperature van der Waals (vdW) ferromagnet Fe3GaTe2 nanoflakes at low temperatures. The observed intrinsic EB effects can be largely tuned via the gate-induced proton intercalation. Moreover, we observe an unusual sign-tunable EB effect under different gate voltages after ±2T field cooling, leading to a crossover between positive and negative EB effects. Theoretical analysis based on density functional theory indicates that the magnetic coupling at the FM/AFM interface in proton-intercalated Fe3GaTe2 is highly controllable and can be tuned to be FMI-1 (↑/↓↑, positive EB) or FMI-2 (↓/↓↑, negative EB) magnetic configurations, depending on different H-absorption sites. Our experiments offer a knob to control the sign of EB effects and further open opportunities for more applicable spintronic devices in high-temperature vdW ferromagnets.

关键词： Exchange bias device fabrication density functional theory

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direct Observation of Void Nucleation and Growth in a 2-µm-Wide Cu redistribution Line during In Situ Electromigration

Direct Observation of Void Nucleation and Growth in a 2-µm-...

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International Conference on Electronics Packaging (ICEP)

作者： Chien-Lung Liang Yung-Sheng Lin Min-Yan Tsai Meng-Chun Chiu Shan-Bo Wang Chih-Pin Hung Kwang-Lung Lin Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei Taiwan Corporate R&D Advanced Semiconductor Engineering (ASE) Group Kaohsiung Taiwan Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan

ISBN: (数字)9784991191176

ISBN: (纸本)9798350385908

In this study, we reported direct observation of void nucleation and growth in a fan-out 2-µm-wide Cu redistribution line (rdL) embedded in polyimide dielectric layers using in situ scanning electron microscope (SEM) investigations. The electromigration experiment was conducted with an extremely high current density of $1.14 \times 10^r\mathrm{A}/\text{cm}^r$ under an ambient condition. Current stressing induced the nucleation, growth, and coalescence of nanovoids on grain boundaries. Nano-scale delamination at the local Cu oxide/Cu rdL interface occurred. The electromigration-induced reliability challenge correlated with the void evolution in the Cu rdL was reported for the failure behavior and mechanism.

关键词： Electromigration Grain boundaries Scanning electron microscopy Failure analysis Polyimides Packaging dielectrics

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Journal of materials Science & technology 2021年第26期85卷 95-105页

作者： Nana Kwabena Adomako Giseung Shin Nokeun Park Kyoungtae Park Jeoung Han Kim Department of Materials Science and Engineering Hanbat National UniversityYuseong-guDaejeon34158Republic of Korea Department of Materials Science and Engineering Pusan National UniversityGeumjeong-guBusan46241Republic of Korea School of Materials Science and Engineering Yeungnam University280 Daehak-roGyeongbuk38541Republic of Korea Rare Metal R&D Group Korea Institute of Industrial TechnologyIncheon21999Republic of Korea

High entropy alloys(HEAs)have superior mechanical properties that have enabled them to be used as structural materials in nuclear and aerospace *** a dissimilar joint design is required for these applications,we created a dissimilar joint between CoCrFeMnNi-HEA and duplex stainless steel(dSS)through laser beam welding;a technique capable of producing a sound joint between the two *** structure examination using SEM/EBSd/Xrd analysis revealed that the weld metal(WM)exhibits an FCC phase regardless of the postweld heat treatment(PWHT)temperature(800 and 1000℃)without forming detrimental intermetallic compounds or *** heat-affected zone of the CoCrFeMnNi-HEA showed CrMn oxide inclusions while that of the dSS showed no ***,a lower hardness was recorded by the WM compared to the base metal after *** PWHT,the hardness of the WM,CoCrFeMnNi-HEA,and dSS decreased with an increase in the PWHT ***,the decrease in the hardness of the HEA was more significant than in the WM and *** cause for this reduction in hardness was attributed to recrystallization and grain *** addition,a strength of 584 MPa with low ductility was recorded after *** obtained strength was lower than that of the BMs,but comparable to that of the welded *** application of PWHT resulted in over a 20%increment in ductility,with only a marginal reduction in *** defo rmation mechanism in the as-weld joint was mainly dominated by dislocation while that for the PWHT joint was *** propose laser beam offset welding as a technique to improve the mechanical properties of the dissimilar joint,which will be the subject of future studies.

关键词： High entropy alloys Welding duplex stainless steel Post-weld heat treatment

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