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Monolithic integration of MoS2-based visible detectors and GaN-based UV detectors

Photonics Research 2019年第10期7卷 1127-1133页

作者： YOU WU ZHIWEN LI KAH-WEE ANG YUPING JIA ZHIMING SHI ZHI HUANG WENJIE YU XIAOJUAN SUN XINKE LIU DABING LI State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore Shenzhen Castle Security Technology Co. Ltd.Shenzhen 518000China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

With the increasing demand for high integration and multi-color photodetection for both military and civilian applications, the research of multi-wavelength detectors has become a new research hotspot. However, current research has been mainly in visible dual-or multi-wavelength detectors, while integration of both visible light and ultraviolet(UV) dual-wavelength detectors has rarely been studied. In this work, large-scale and high-quality monolayer MoS2 was grown by the chemical vapor deposition method on transparent free-standing GaN substrate. Monolithic integration of MoS2-based visible detectors and GaN-based UV detectors was demonstrated using common semiconductor fabrication technologies such as photolithography, argon plasma etching, and metal deposition. High performance of a 280 nm and 405 nm dual-wavelength photodetector was *** responsivity of the UV detector reached 172.12 A/W, while that of the visible detector reached 17.5 A/***, both photodetectors achieved high photocurrent gain, high external quantum efficiency, high normalized detection rate, and low noise equivalent power. Our study extends the future application of dual-wavelength detectors for image sensing and optical communication.

关键词： visible integration ultraviolet

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Deep reinforcement learning for fresh data collection in UAV-assisted IoT networks

arXiv

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arXiv 2020年

作者： Yi, Mengjie Wang, Xijun Liu, Juan Zhang, Yan Bai, Bo State Key Lab of Integrated Service Networks Information Science Institute Xidian University Xi’an Shaanxi710071 China Science and Technology on Communication Network Laboratory Shijiazhuang Hebei050081 China School of Electronics and Communication Engineering Sun Yat-sen University Guangzhou510006 China Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai200050 China School of Electrical Engineering and Computer Science Ningbo University Zhejiang315211 China 2012 Labs Huawei Technologies Co. Ltd. Hong Kong Hong Kong

Due to the flexibility and low operational cost, dispatching unmanned aerial vehicles (UAVs) to collect information from distributed sensors is expected to be a promising solution in Internet of Things (IoT), especially for time-critical applications. How to maintain the information freshness is a challenging issue. In this paper, we investigate the fresh data collection problem in UAV-assisted IoT networks. Particularly, the UAV flies towards the sensors to collect status update packets within a given duration while maintaining a non-negative residual energy. We formulate a Markov Decision Process (MDP) to find the optimal flight trajectory of the UAV and transmission scheduling of the sensors that minimizes the weighted sum of the age of information (AoI). A UAV-assisted data collection algorithm based on deep reinforcement learning (DRL) is further proposed to overcome the curse of dimensionality. Extensive simulation results demonstrate that the proposed DRL-based algorithm can significantly reduce the weighted sum of the AoI compared to other baseline algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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The developing condition analysis of semiconductor laser frequency stabilization technology

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Journal of Semiconductors 2018年第11期39卷 40-46页

作者： Yijun Yao Canwen Zou Haiyang Yu Jinjin Guo Yaming Li Jianguo Liu State Key Laboratory on Integrated Optoelectronics Institution of Semiconductors Chinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Key Laboratory of Aerospace Information Applications CETC College of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences

The frequency stability of free-running semiconductor lasers is influenced by several factors, such as driving current and external operating environment. The frequency stabilization of laser has become an international research hotspot in recent years. This paper reviews active frequency stabilization technologies of laser diodes and elaborates their principles. Based on differences of frequency discrimination curves, these active frequency stabilization technologies are classified into three major types, which are harmonic frequency stabilization,Pound-Drever-Hall(PDH) technology and curve subtraction frequency stabilization. Further, merits and demerits of each technology are compared from aspects of frequency stability and structure complexity. Finally, prospects of frequency stabilization technologies of semiconductor lasers are discussed in detail. Combining several of these methods are future trends, especially the combination of frequency stabilization of F–P cavity. And PID electronic control for optimizing the servo system is generally added in the methods mentioned above.

关键词： semiconductor laser frequency stabilization active frequency stabilization frequency discriminator

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A high current gain 4H-SiC BJT of novel epitaxial passivation structure

A high current gain 4H-SiC BJT of novel epitaxial passivatio...

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International Conference on Silicon Carbide and Related Materials, ICSCRM 2017

作者： Zhang, You Run Wang, Wen Li, Ming Ye Guo, Fei Li, Jun Tao Li, Xuan The State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China Microsystem and Terahertz Research Center China Academy of Engineering Physics Chengdu China

ISBN: (纸本)9783035711455

This paper proposes a novel high-gain 4H-SiC BJT structure with a p-type epitaxial layer on top of the extrinsic base layer. The current gain of the novel structure is improved by 140% compared with the conventional one by the simulator tool with the number of reasonable interface traps, which could be ascribed to the epitaxial layer to reduce the surface recombination in the extrinsic base. The process to fabricate this structure is also proposed in the paper. © 2018 Trans Tech Publications, Switzerland.

关键词： Silicon carbide

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Large graphene-induced shift of surface-plasmon resonances of gold films: Effective-medium theory for atomically thin materials

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Physical Review Research 2020年第1期2卷 013008-013008页

作者： Md Kamrul Alam Chao Niu Yanan Wang Wei Wang Yang Li Chong Dai Tian Tong Xiaonan Shan Earl Charlson Steven Pei Xiang-Tian Kong Yandi Hu Alexey Belyanin Gila Stein Zhaoping Liu Jonathan Hu Zhiming Wang Jiming Bao Materials Science and Engineering University of Houston Houston Texas 77204 USA Department of Electrical & Computer Engineering Baylor University Waco Texas 76798 USA Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu Sichuan 610054 China Department of Electrical and Computer Engineering University of Houston Houston Texas 77204 USA Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences Ningbo Zhejiang 315201 China Key Laboratory of Graphene Technologies and Applications of Zhejiang Province Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo Zhejiang 315201 China Department of Civil and Environmental Engineering University of Houston Houston Texas 77204 USA Department of Physics & Astronomy Texas A&M University College Station Texas 77843 USA Chemical and Biomolecular Engineering The University of Tennessee Knoxville Tennessee 37996 USA State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu Sichuan 610054 China

Despite successful modeling of graphene as a 0.34-nm-thick optical film synthesized by exfoliation or chemical vapor deposition (CVD), graphene-induced shift of surface-plasmon resonance (SPR) of gold films has remained controversial. Here we report the resolution of this controversy by developing a clean CVD graphene transfer method and extending Maxwell-Garnett effective-medium theory (EMT) to two-dimensional (2D) materials. A SPR shift of 0.24° is obtained and it agrees well with 2D EMT in which wrinkled graphene is treated as a 3-nm graphene/air layered composite, in agreement with the average roughness measured by atomic force microscopy. Because the anisotropic built-in boundary condition of 2D EMT is compatible with graphene's optical anisotropy, graphene can be modeled as a film thicker than 0.34 nm without changing its optical property; however, its actual roughness, i.e., effective thickness, will significantly alter its response to strong out-of-plane fields, leading to a larger SPR shift.

关键词： Dielectric properties Optical conductivity Plasmonics Plasmons Refraction

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Wavelength‐selective wavefront shaping by metasurface^＊#

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Frontiers of Information Technology & Electronic engineering 2023年第4期24卷 617页

作者： Zixin CAI XinHE Xin LIU Shijie TU Xinjie SUN Paul BECKETT Aditya DUBEY Arnan MITCHELL GuanghuiREN Xu LIU XiangHAO Zhejiang University State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Technology Hangzhou China (GRID:grid.13402.34) (ISNI:0000 0004 1759 700X) RMIT University School of Engineering Melbourne Australia (GRID:grid.1017.7) (ISNI:0000 0001 2163 3550) RMIT University Integrated Photonics and Applications Centre (InPAC) Melbourne Australia (GRID:grid.1017.7) (ISNI:0000 0001 2163 3550) Zhejiang University State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Technology Hangzhou China (GRID:grid.13402.34) (ISNI:0000 0004 1759 700X) Jiaxing Research Institute Zhejiang University Intelligent Optics & Photonics Research Center Jiaxing China (GRID:grid.13402.34) (ISNI:0000 0004 1759 700X) Jiaxing Key Laboratory of Photonic Sensing & Intelligent Imaging Jiaxing China (GRID:grid.13402.34)

摘要精确的、与波长相关的相位调制在许多领域中是必不可少的, 比如超分辨成像、全彩色全息、微纳加工以及光通讯。这一要求很难通过单一的传统光学元件实现, 一般需要使用多个光学元件组合完成。本文提出一种可以实现波长选择性波前整...

摘要精确的、与波长相关的相位调制在许多领域中是必不可少的, 比如超分辨成像、全彩色全息、微纳加工以及光通讯。这一要求很难通过单一的传统光学元件实现, 一般需要使用多个光学元件组合完成。本文提出一种可以实现波长选择性波前整形的超表面设计方法。具体来说, 本文设计了一种超表面, 它能够对785 nm波长的光做涡旋相位调制, 同时不影响590 nm波长的光保持原有相位分布。本文通过干涉仪以及对应点扩散函数的测量来验证不同波长下的波前分布。与已提出的空间复用方式以及色散工程的方法相比, 我们提出的设计方法更加直接, 优化难度小, 适用于需要波长选择性编码的光学系统。本文所提平面光学器件对于需要波长选择性编码的光学系统具有重要应用意义。

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Controlled Deformation of Soft Nanogel Particles Generates Artificial Biominerals with Ordered Internal Structure

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Angewandte Chemie 2023年第19期135卷

作者： Yingxiang Dong Dr. Jialin Chi Zelun Ren Biao Xiong Ziqing Liu Wenjun Zhang Prof. Lijun Wang Prof. Syuji Fujii Prof. Steven P. Armes Prof. Yin Ning College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications Jinan University Guangzhou 510632 China College of Resources and Environment Huazhong Agricultural University Wuhan 430070 China Present address: National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agroenvironmental Pollution Control and Management Institute of Eco-environmental and Soil Sciences Guangdong Academy of Sciences Guangzhou 510650 China Department of Applied Chemistry Faculty of Engineering and Nanomaterials Microdevices Research Center Osaka Institute of Technology 5-16-1 Omiya Asahi-ku Osaka 535-8585 Japan Department of Chemistry University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK

Biominerals can exhibit exceptional mechanical properties owing to their hierarchically-ordered organic/inorganic nanocomposite structure. However, synthetic routes to oriented artificial biominerals of comparable complexity remain a formidable technical challenge. Herein we design a series of soft, deformable nanogels that are employed as particulate additives to prepare nanogel@calcite nanocomposite crystals. Remarkably, such nanogels undergo a significant morphological change—from spherical to pseudo-hemispherical—depending on their degree of cross-linking. This deformation occurs normal to the growth direction of the (104) face of the calcite and the underlying occlusion mechanism is revealed by in situ atomic force microscopy studies. This model system provides new mechanistic insights regarding the formation of oriented structures during biomineralization and offers new avenues for the design of synthetic nanocomposites comprising aligned anisotropic nanoparticles.

关键词： Biomineralization Nanogels Nanoparticle Occlusion Organic/Inorganic Nanocomposite Crystals Orientation

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A Universal Self-Propagating Synthesis of Aluminum-Based Oxyhalide Solid-State Electrolytes

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Angewandte Chemie 2024年第27期136卷

作者： Dr. Simeng Zhang Yang Xu Han Wu Tianlu Pang Dr. Nian Zhang Prof. Changtai Zhao Junyi Yue Dr. Jiamin Fu Shengjie Xia Xiangzhen Zhu Guanzhi Wang Dr. Hui Duan Prof. Biwei Xiao Dr. Tao Mei Prof. Jianwen Liang Prof. Xueliang Sun Prof. Xiaona Li Eastern Institute for Advanced Study Eastern Institute of Technology Ningbo Zhejiang 315200 P. R. China Solid State Batteries Research Center GRINM (Guangdong) Institute for Advanced Materials and Technology Foshan Guangdong 528051 P. R. China School of Materials Science and Engineering Hubei University Wuhan 430062 P. R. China National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050. P. R. China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201204 P. R. China Department of Mechanical and Materials Engineering University of Western Ontario London ON N6A 5B9 Canada

Inorganic solid-state electrolytes (SSEs) play a vital role in high-energy all-solid-state batteries (ASSBs). However, the current method of SSE preparation usually involves high-energy mechanical ball milling and/or a high-temperature annealing process, which is not suitable for practical application. Here, a facile strategy is developed to realize the scalable synthesis of cost-effective aluminum-based oxyhalide SSEs, which involves a self-propagating method by the exothermic reaction of the raw materials. This strategy enables the synthesis of various aluminum-based oxyhalide SSEs with tunable components and high ionic conductivities (over 10 −3 S cm −1 at 25 °C) for different cations (Li + , Na + , Ag + ). It is elucidated that the amorphous matrix, which mainly consists of various oxidized chloroaluminate species that provide numerous sites for smooth ion migration, is actually the key factor for the achieved high conductivities. Benefit from their easy synthesis, low cost, and low weight, the aluminum-based oxyhalide SSEs synthesized by our approach could further promote practical application of high-energy-density ASSBs.

关键词： self-propagating synthesis oxyhalide solid electrolyte solid-state electrolyte superionic conductor all-solid-state battery

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Influence of carrier gas H2 flow rate on quality of p-type GaN epilayer grown and annealed at lower temperatures

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Chinese Physics B 2018年第12期27卷 499-503页

作者： Shuang-Tao Liu Jing Yang De-Gang Zhao De-Sheng Jiang Feng Liang Ping Chen Jian-Jun Zhu Zong-Shun Liu Wei Liu Yao Xing Li-Yuan Peng Li-Qun Zhang Wen-Jie Wang Mo Li State Key Laboratory of Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China Suzhou Institute of Nanotech and Nanobionics Chinese Academy of SciencesSuzhou 215123China Microsystem&Terahertz Research Center Chinese Academy of Engineering PhysicsChengdu 610200China

In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effectively decrease with appropriately reducing the carrier gas H2flow rate, and a high-quality p-type GaN layer could be obtained at a comparatively low annealing temperature by reducing the carrier gas H2flow rate. Meanwhile, it is found that the intensity and wavelength of DAP peak are changed as the annealing temperature varies, which shows that the thermal annealing has a remarkable effect not only on the activation of acceptors but also on the compensation donors.

关键词： p-type GaN thermal annealing H atom state

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How to pressureless sinter-bond power chips with bare copper substrates using nanosilver paste?

How to pressureless sinter-bond power chips with bare copper...

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International Conference on (ICEPT) Electronic Packaging Technology

作者： Yue Chen Yunhui. Mei Zhihong Feng Panpan Lu Meiyu Wang Yingkun Yang Guo-Quan Lu School of Materials Science and Engineering Tianjin University Tianjin P. R. China National Key Laboratory of Application Specific Integrated Circuit (ASIC) Hebei Semiconductor Research Institute Shijiazhuang China Microsystem and Terahertz Research Center China Academy of Engineering Physics Chengdu P.R. China Department of Materials Science and Engineering Virginia Tech Blacksburg USA

ISBN: (数字)9781728150642

ISBN: (纸本)9781728150659

Nanosilver paste pressureless sintering for bonding power semiconductor devices have been widely used. However, most of the substrates used are silver- or gold-coated substrates. Additional coatings will increase the manufacture cost, reduce the production efficiency, and cause problems with the coating lamination. The bonding process was carried out by sintering nanosilver paste on bare copper DBC substrates in different reducing atmospheres in this study. Three different reducing atmospheres were used as comparison: i.e., (1) sintering in pure nitrogen (N2), (2) sintering in 4% hydrogen and 96% nitrogen (4%H2/N2), and (3) two-step sintering profile: drying in the air in the first step and then sintering in 4%H2/N2 in the second step. The bonding strength of sintered joints was evaluated by the shear test. The highest bonding strength can be obtained by the two-step sintering. The average shear strength obtained by the two-step sintering method is more than 40 MPa at the peak temperature of 310°C. It can be seen that the sintering atmosphere has a critical effect on the density of the joints. The sintered joints with the highest density were obtained by the two-step sintering method. Many necks were formed between the silver particles during the sintering.

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