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Terahertz Direct Modulation Techniques for High-speed Communication Systems

China Communications 2021年第5期18卷 221-244页

作者： Tianchi Zhou Yaxin Zhang Bo Zhang Hongxin Zeng Zhiyong Tan Xilin Zhang Lan Wang Zhi Chen Juncheng Cao Kaijun Song Ziqiang Yang University of Electronic Science and Technology of China ChengduChina Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou 313001China Key Laboratory of Terahertz Solid State Technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences865 Changning RoadShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Terahertz communication technology can provide abundant frequency resources,strong confidentiality,antijamming capability,communication tracking capability and the ability to achieve highspeed data transmissions and can serve as an important technical method for high-speed communications in the *** these terahertz communication technologies,terahertz direct modulation technology is a key means to achieve low system complexity and power *** this paper,a review and outlook of terahertz direct modulation technology are proposed from the aspects of high-electron-mobilitytransistor-based terahertz direct modulation,parallelswitch terahertz direct modulation,diode-based terahertz direct modulation,quantum cascade laser-based terahertz direct modulation and new-material-based terahertz direct *** hope through this paper that more readers can gain knowledge about the development and challenges of terahertz direct modulation technology for high-speed communication systems,thus promoting the development of high-speed terahertz communication technology based on direct modulation.

关键词： THz communication THz direct modulation HEMT switches diode QCL new-material

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Challenges and opportunities facing zinc anodes for aqueous zinc-ion battery

Energy Materials and Devices

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Energy materials and Devices 2024年第3期2卷 30-50页

作者： Boyu Li Yuetao Ma Jiabin Ma Likun Chen Yang Zhao Man-Chung Tang Shenzhen All-Solid-State Lithium Battery Electrolyte Engineering Research Center Institute of Materials Research(IMR)Tsinghua Shenzhen International Graduate SchoolShenzhen 518055China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

Rechargeable aqueous zinc-ion batteries(ZIBs)have gained attention as promising candidates for nextgeneration large-scale energy storage systems due to their advantages of improved safety,environmental sustainability,and low ***,the zinc metal anode in aqueous ZIBs faces critical challenges,including dendrite growth,hydrogen evolution reactions,and corrosion,which severely compromise Coulombic efficiency and cycling stability,hindering their broader *** review first explores the fundamental mechanisms underlying these challenges and then examines current strategies to address them,focusing on structural design,surface modifications,electrolyte optimization,and alloying ***,potential future directions are discussed,outlining a pathway toward achieving high-performance aqueous ZIBs.

关键词： aqueous zinc-ion batteries zinc metal anode structural design surface modification electrolyte optimization alloying anode

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Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

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Chemistry of materials 2023年第17期35卷 7273-7282页

作者： Ou, Xun Luo, Junfeng Zhang, Jiliang Chen, Chi-Liang Yu, Jing Hu, Jiawei Chang, Chung-Kai Moudrakovski, Igor Lau, Vincent Wing-Hei Zhao, Ruirui South China Normal University Guangzhou510006 China School of Materials Science and Engineering Dalian Jiaotong University Dalian116028 China National Synchrotron Radiation Research Center Hsinchu30076 Taiwan CSIC and BIST Campus UAB Bellaterra Catalonia Barcelona08193 Spain Max Planck Institute for Solid State Research Heisenbergstraße 1 Stuttgart70569 Germany Department of Chemistry National Cheng Kung University Tainan City701 Taiwan

Doping could effectively tune the electrochemical performance of layered oxide cathodes in Li-ion batteries, whereas the working mechanism is usually oversimplified (i.e., a "pillar" effect). Although the Jahn-Teller effect is generally regarded as the fundamental origin of structural instability in some oxides, more polyhedral distortions are associated with pseudo-JTE (PJTE), which involves vibronic couplings. In this work, the atomic structures of doped LiCoO2 by Mg cations, F anions, and both were investigated thoroughly to reveal the atomic environments of these dopants and their influence on electrochemical performance. The function of these dopants as pillars is well discussed from the view of PJTE manipulation. Briefly, the MgO4 tetrahedra in Mg-doped LiCoO2 could suppress the charge transfer from the ligand to Co in neighboring octahedra, thus depressing PJTE. Although F doping does increase the ligand-field strength, the induced octahedral distortion reduces the structural stability dramatically. Comparatively, Mg/F co-doping generates the CoO5F-MgO4F2-CoO5F medium-range orders (MROs), which could depress both structural distortion and charge transfer in Co-centered octahedra for reduced PJTE. The reduced PJTE accounts for the improved electrochemical performance, making the co-doped LiCoO2 offer the best performance: a 70% capacity retention after 200 cycles within the potential range of 2.8-4.6 V, followed by Mg-doped LiCoO2. In contrast, although F-doping could induce an extra rock salt-like surface layer for higher capacity, its cycling improvement is rather limited. These results highlight the importance of structural modulation in enhancing the material performance and propose that the manipulation of PJTE would be an effective strategy in developing novel high-performance oxide cathodes. © 2023 American Chemical Society.

关键词： Charge transfer

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Effect of Raw Material Fineness on the Properties of Inorganic Foam materials from solid Waste

SSRN

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SSRN 2024年

作者： Gao, Yongshuai Zhao, Qingxin Guo, Weichao He, Zhiheng Wang, Tongqiu State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066000 China Hebei Province Urban Solid Waste Harmless Collaborative Treatment and Recycling Engineering Research Center Yanshan University Qinhuangdao066000 China

solid waste inorganic lightweight materials not only compensate for the flammability of organic materials but also have a lower carbon footprint. They are environmentally safe and cost-effective compared with cement-based foaming materials, and they have good development prospects. This study aimed to improve the chemical foaming reaction kinetics by reducing the particle size of aluminum powder and alkaline solid waste, thereby increasing the expansion degree of solid waste slurry, to further reduce the absolute dry density of inorganic lightweight materials for solid waste and optimize their performance. The influence of the particle size of raw material on the absolute dry density, water absorption, and compressive strength of lightweight materials was investigated. The influence of the particle size of raw material on the macroscopic pore structure of foamed materials was analyzed through binarization of cross-sectional images of specimens. Furthermore, the hydration products and microstructure of materials were characterized using XRD, FTIR, TG-DTG, and SEM to provide a theoretical basis for related research. The experimental results showed that the smaller the particle size of the raw material, the easier it was to carbonize and the lower the flowability of the corresponding cementitious material slurry. Reducing the particle size of raw materials and aluminum powder increased the degree of slurry expansion, thereby reducing the absolute dry density of foaming materials. In addition, reducing the particle size of raw materials and using carbide slag wastewater instead of tap water increased the degree of foaming reaction and hydration reaction, which helped C-(A)-S-H gel formation and promoted the development of sample strength. Finally, the absolute dry density of inorganic lightweight materials was reduced to 0.35 g/cm3 at the minimum, and the corresponding 28-day compressive strength was 0.28 MPa, which met the requirements of the JG/T 266-2011 "foam concre

关键词： Particle size

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Stabilizing polar phases in binary metal oxides by hole doping

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Physical Review materials 2023年第4期7卷 044412-044412页

作者： Tengfei Cao Guodong Ren Ding-Fu Shao Evgeny Y. Tsymbal Rohan Mishra Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience University of Nebraska Lincoln Nebraska 68588-0299 USA Department of Mechanical Engineering & Materials Science Washington University in St. Louis St. Louis Missouri 63130 USA Institute of Materials Science & Engineering Washington University in St. Louis St. Louis Missouri 63130 USA Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei 230031 China

The recent observation of ferroelectricity in the metastable phases of binary metal oxides, such as HfO2, ZrO2, Hf0.5Zr0.5O2, and Ga2O3, has garnered a lot of attention. These metastable ferroelectric phases are typically stabilized using epitaxial strain, alloying, or defect engineering. Here, we propose that hole doping plays a key role in the stabilization of polar phases in binary metal oxides. Using first-principles density-functional-theory calculations, we show that holes in these oxides mainly occupy one of the two oxygen sublattices. This hole localization, which is more pronounced in the polar phase than in the nonpolar phase, lowers the electrostatic energy of the system, and makes the polar phase more stable at sufficiently large concentrations. We demonstrate that this electrostatic mechanism is responsible for stabilization of the ferroelectric phase of HfO2 aliovalently doped with elements that introduce holes to the system, such as La and N. Finally, we show that spontaneous polarization in HfO2 is robust to hole doping, and a large polarization persists even under a high concentration of holes.

关键词： Charge Density of states Doping effects Electric polarization Electronic structure Ferroelectricity

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Field distribution of the Z_(2)topological edge state revealed by cathodoluminescence nanoscopy

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Opto-Electronic Advances 2022年第4期5卷 76-84页

作者： Xiao He Donglin Liu Hongfei Wang Liheng Zheng Bo Xu Biye Xie Meiling Jiang Zhixin Liu Jin Zhang Minghui Lu Zheyu Fang School of Physics State Key Lab for Mesoscopic PhysicsAcademy for Advanced Interdisciplinary StudiesCollaborative Innovation Center of Quantum Matterand Nano-optoelectronics Frontier Center of Ministry of EducationPeking University Yangtze Delta Institute of OptoelectronicsPeking UniversityBeijing 100871China National Laboratory of Solid State Microstructures Department of Materials Science and EngineeringNanjing UniversityNanjing 210093China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Department of Physics and HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong the University of Hong KongPokfulam RoadHong KongChina

Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission,such as unidirectional waveguide and single-mode ***,because of the diffraction limit of light,the physical insight of topological resonance remains unexplored in detail,like the dark line that exists with the crys-talline symmetry-protected topological edge ***,we experimentally observe the dark line of the Z_(2)photonic topo-logical insulator in the visible range by photoluminescence and specify its location by cathodoluminescence characteriza-tion,and elucidate its mechanism with the p-d orbital electromagnetic field distribution which calculated by numerical *** investigation provides a deeper understanding of Z_(2)topological edge states and may have great signific-ance to the design of future on-chip topological devices.

关键词： photonic topological insulator edge state cathodoluminescence TMDC

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Highly efficient electroluminescence from Si quantum dot/SiO2 multilayer light-emitting devices via phosphorus/boron co-doping and surface nano-structuring

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Optics letters 2025年第12期50卷 3927-3930页

作者： Junnan Han Yuhao Wang Jiaming Chen Teng Sun Dongke Li Wei Li Ling Xu Jun Xu Kunji Chen National Laboratory of Solid State Microstructures School of Electronic Science and Engineering Collaborative Innovation Center of Advanced Microstructures Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials Nanjing University Nanjing 210093 China State Key Laboratory of Silicon and Advanced Semiconductor Materials ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Materials Science and Engineering Zhejiang University Hangzhou 311200 China ldkest@*** School of Microelectronics and School of Integrated Circuits and Jiangsu Key Laboratory of Semi. Dev. & IC Design Package and Test Nantong University Nantong 226019 China

Enhancing emission efficiency presents a challenge for Si-based light emission devices in all-silicon monolithic optoelectronic integration. This study introduces phosphorus (P)/boron (B) co-doping to significantly increase the electroluminescence intensity of Si quantum dots (QDs)-nearly tenfold compared to undoped devices. The turn-on voltage drops from 15 V for undoped to 6 V for co-doped devices and further reduces to 3 V with a nanostructured Si substrate to improve light extraction efficiency. The redshift of electroluminescence peak after co-doping is also observed, and the possible mechanism is briefly discussed. Stability tests show power efficiency up to 1.02% and maximum external quantum efficiency of 4.9%. These findings demonstrate the superior optoelectronic quality and stability of silicon nanomaterial-based devices, highlighting their potential in integrated silicon photonics.

关键词： Integrated photonics Light extraction Quantum dots Quantum efficiency Scanning electron microscopy Silicon photonics

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Activation of Ultra-Fine Steel Slag and Ground Granulated Blast Furnace Slag in Alkaline Waste Solutions Via Phosphogypsum and Calcium Carbide Slag

SSRN

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SSRN 2024年

作者： Guo, Rui Xue, Caihong Guo, Weichao Pan, Huimin Zhao, Qingxin State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066000 China Hebei Province Engineering Research Center for Harmless Synergistic Treatment and Recycling of Municipal Solid Waste Yanshan University Qinhuangdao066000 China

To deal with the growing demand for efficient treatment of industrial solid wastes for a better environment, this study expands the ways of utilizing multiple solid wastes. SRL (soda residue liquid) obtained by filtrating soda residue from ammonia-soda production, The pH of SRL ranges from 11.9 to 12.1, indicating a significant alkalinity akin to the pore solution of cementitious materials. As such, it can be deemed a viable substitute for tap water in the capacity of mixing water. PG (phosphogypsum) is derived from the fertilizer production process and, once purified, can function as an alternative to traditional sulfate activators. CS (calcium carbide slag), derived from the acetylene production process, currently serves as a widely utilized alkaline *** test results demonstrate that the composite system achieves a 28-day strength of up to 60 MPa. The effect of SS content on the hydration kinetics, setting time, compressive strength was investigated. To elucidate the role of SS and PG in the reaction, the hydration products were characterized with TGA, XRD and *** results suggest that the Cl- in SRL undergoes effective immobilization within the system, thereby filling the gel pores as Friedel’s salt (Fs) and facilitating the formation of a dense structure. Utilizing Rietveld Refinement technology to quantitative analysis in the content of crystalline phases within the pastes. Q-XRD coupled with TGA was utilized to analyze the changes in crystalline and non-crystalline phases within the system, revealing the hydration mechanism of the hydration mechanism of steel slag activated by physical, chemical, and mineral factors in a alkaline waste solutions environment. © 2024, The Authors. All rights reserved.

关键词： Compressive strength

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Demonstration of Acoustic Higher-Order Topological Stiefel-Whitney Semimetal

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Physical Review Letters 2024年第19期132卷 197202-197202页

作者： Xiao Xiang Yu-Gui Peng Feng Gao Xiaoxiao Wu Peng Wu Zhaoxian Chen Xiang Ni Xue-Feng Zhu School of Physics and Innovation Institute Huazhong University of Science and Technology Wuhan 430074 China Quantum Science and Technology Center and Advanced Materials Thrust The Hong Kong University of Science and Technology (Guangzhou) Nansha Guangzhou 511400 Guangdong China Department of Physics The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China College of Engineering and Applied Sciences Collaborative Innovation Center of Advanced Microstructures and National Laboratory of Solid State Microstructures Nanjing University Nanjing 210023 China School of Physics Central South University Changsha 410083 China

The higher-order topological phases have attracted intense attention in the past years, which reveals various intriguing topological properties. Meanwhile, the enrichment of group symmetries with projective symmetry algebras redefines the fundamentals of topological matter and makes Stiefel-Whitney (SW) classes in classical wave systems possible. Here, we report the experimental realization of higher-order topological nodal loop semimetal in an acoustic system and obtain the inherent SW topological invariants. In stark contrast to higher-order topological semimetals relating to complex vector bundles, the hinge and surface states in the SW topological phase are protected by two distinctive SW topological charges relevant to real vector bundles. Our findings push forward the studies of SW class topology in classical wave systems, which also show possibilities in robust high-Q-resonance-based sensing and energy harvesting.

关键词： Acoustic metamaterials Phononic crystals Semimetals Topology

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由原子薄横向异质结构建的可调谐肖特基二极管

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science China materials 2023年第11期66卷 4419-4426页

作者：卢香超王伟朱慧洁吴永森鲁艺珍邵功磊刘松曹阳 State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityZhengzhou 450001China Institute of Chemical Biology and Nanomedicine(ICBN) State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China

本研究利用一步化学气相沉积技术制备了Sn_(x)Mo_(1−x)S_(2)/MoS_(2)横向异质结高性能二极管.通过选择性掺杂Sn原子到单层MoS_(2)的边缘,形成了与MoS_(2)相同晶格常数的Sn_(x)Mo_(1−x)S_(2).在边缘的Sn_(x)Mo_(1−x)S_(2)和内部的MoS_(2)上分别沉积铬/金电极,形成肖特基势垒,其中势垒高度不同导致载流子仅在一个方向上传输.通过控制掺杂浓度和栅极电压,可实现MoS_(2)和Sn_(x)Mo_(1−x)S_(2)之间费米能级的对齐调节,实现了可调整的整流比,最高达到104.令人印象深刻的是,该二极管还表现出优异的光伏特性,该器件在λ=400 nm处实现了40%的外量子效率值.此外,我们在无外部偏压条件下实现了自供电光电探测,该异质结二极管在400和650 nm波长处的响应率分别为0.12和0.16 A W^(-1).对应的探测率分别是4.9×10^(10)和6.4×10^(10)Jones.可调的掺杂浓度为进一步创造高效器件提供了可能.这种合成二维侧向二极管的策略丰富了异质结二极管的材料多样性,并为开发新型电子和光电器件提供了新的平台.

关键词： heterojunction diode controllable doping tunable rectification ratio one-step chemical vapor deposition photo-voltaic effect

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