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Progress in efficient doping of Al-rich AlGaN

Journal of Semiconductors 2024年第2期45卷 10-20页

作者： Jiaming Wang Fujun Xu Lisheng Zhang Jing Lang Xuzhou Fang Ziyao Zhang Xueqi Guo Chen Ji Chengzhi Ji Fuyun Tan Xuelin Yang Xiangning Kang Zhixin Qin Ning Tang Xinqiang Wang Weikun Ge Bo Shen State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Beijing SinoGaN Semiconductor Technology Co. Ltd.Beijing 101399China Nano-optoelectronics Frontier Center of Ministry of Education Peking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China

The development of semiconductors is always accompanied by the progress in controllable doping *** AlGaN-based ultraviolet(UV)emitters as an example,despite a peak wall-plug efficiency of 15.3%at the wavelength of 275 nm,there is still a huge gap in comparison with GaN-based visible light-emitting diodes(LEDs),mainly attributed to the inefficient doping of AlGaN with increase of the Al ***,p-doping of Al-rich AlGaN is a long-standing challenge and the low hole concentration seriously restricts the carrier injection *** p-GaN cladding layers are widely adopted as a compromise,the high injection barrier of holes as well as the inevitable loss of light extraction cannot be *** in terms of n-doping the main issue is the degradation of the electrical property when the Al composition exceeds 80%,resulting in a low electrical efficiency in sub-250 nm *** review summarizes the recent advances and outlines the major challenges in the efficient doping of Al-rich AlGaN,meanwhile the corresponding approaches pursued to overcome the doping issues are discussed in detail.

关键词： AlGaN-based UV-LEDs Al-rich AlGaN doping

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Sub-nanometer ultrathin epitaxy of AlGaN and its application in efficient doping

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Light(Science & Applications) 2022年第4期11卷 654-661页

作者： Jiaming Wang Mingxing Wang Fujun Xu Baiyin Liu Jing Lang Na Zhang Xiangning Kang Zhixin Qin Xuelin Yang Xinqiang Wang Weikun Ge Bo Shen State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking University100871 BeijingChina Nano-optoelectronics Frontier Center of Ministry of Education Peking University100871 BeijingChina Collaborative Innovation Center of Quantum Matter 100871 BeijingChina

Solving the doping asymmetry issue in wide gap semiconductors is a key dificulty and long-standing challenge for device ***,a desorption-tailoring strategy is proposed to juggle the carrier concentration and *** to the p-doping issue in Al-rich AlGaN,self-assembled p-AlGaN superlattices with an average Al composition of over 50%are prepared by adopting this *** hole concentration as high as 8.1×10^(18)cm^(-3)is thus realized at room temperature,which is attributed to the signifcant reduction of effective Mg activation energy to 17.5 meV through modulating the activating path,as well as the highlighted Mg surface-incorporation by an intentional interruption for *** importantly,benefting from the constant ultrathin barrier thickness of only three monolayers via this approach,vertical miniband transport of holes is verifed in the p-AlGaN superlattices,greatly satisfying the demand of hole injection in device application.280 nm deep-ultraviolet light emitting diodes are then fabricated as a demo with the desorption-tailored Al-rich p-AlGaN superlattices,which exhibit a great improvement of the carrier injection efficiency and light extraction efficiency,thus leading to a 55.7%increase of the light output *** study provides a solution for p-type doping of Al-rich AlGaN,and also sheds light on solving the doping asymmetry issue in general for wide-gap semiconductors.

关键词： AlGaN ultrathin GaN

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High-Temperature Superconducting YBa_(2)Cu_(3)O_(7-δ)Josephson Junction Fabricated with a Focused Helium Ion Beam

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Chinese physics Letters 2022年第7期39卷 87-92页

作者： Ziwen Chen Yulong Li Rui Zhu Jun Xu Tiequan Xu Dali Yin Xinwei Cai Yue Wang Jianming Lu Yan Zhang * and Ping Ma Applied Superconductivity Research Center Peking UniversityBeijing 100871China State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Peking UniversityBeijing 100871China School of Physics Peking UniversityBeijing 100871China Electron Microscopy Laboratory School of PhysicsPeking UniversityBeijing 100871China

As a newly developed method for fabricating Josephson junctions,a focused helium ion beam has the advantage of producing reliable and reproducible *** fabricated Josephson junctions with a focused helium ion beam on our 50 nm YBa_(2)Cu_(3)O_(7-δ)(YBCO)thin *** focused on the junction with irradiation doses ranging from 100 to 300 ions/nm and demonstrated that the junction barrier can be modulated by the ion dose and that within this dose range,the junctions behave like superconductor–normal conductor–superconductor *** measurements of the I–V characteristics,Fraunhofer diffraction pattern,and Shapiro steps of the junctions clearly show AC and DC Josephson *** findings demonstrate high reproducibility of junction fabrication using a focused helium ion beam and suggest that commercial devices based on this nanotechnology could operate at liquid nitrogen temperatures.

关键词： Josephson Junction Fabricated with a Focused Helium Ion Beam High-Temperature Superconducting YBa_(2)Cu_(3)O

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Spin texture and tunneling magnetoresistance in atomically thin CrSBr

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Physical Review B 2025年第14期111卷 L140417-L140417页

作者： Ziqi Liu Yichang Sun Chengfeng Zhu Canyu Hong Yuchen Gao Zeyuan Sun Kenji Watanabe Takashi Taniguchi Shiwei Wu Zuxin Chen Pingfan Gu Yu Ye State Key Laboratory for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University Beijing 100871 China State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Physics Fudan University Shanghai 200433 China Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 304-0044 Japan School of Semiconductor Science and Technology South China Normal University Foshan 528225 China MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Department of Applied Physics Nanjing University of Science and Technology Nanjing 210094 China Collaborative Innovation Center of Quantum Matter Beijing 100871 China Liaoning Academy of Materials Shenyang 110167 China

The exploration of spin configurations and magnetoresistance in van der Waals magnetic semiconductors, particularly in the realm of thin-layer structures, is of paramount significance for the development of two-dimensional spintronic nanodevices. In this Letter, we present detailed magnetotransport and photoluminescence studies on few-layer CrSBr flakes utilizing a vertical tunneling device configuration. Our investigations revealed complex magnetic states along the evolutionary path of few-layer CrSBr. We observed intermediate states exhibiting identical net magnetization demonstrate rectification properties, reminiscent of a diodelike behavior at positive and negative bias voltages. Notably, in devices with five-layer CrSBr, we detected an intriguing positive magnetoresistive state when subjected to an in-plane magnetic field along the b axis. The implementation of the Mott two-current model successfully calculated the tunneling resistance of different magnetic states, thereby elucidating the spin configurations responsible for the observed transport phenomena. These insights not only provide different perspectives on the intricate spin textures of two-dimensional CrSBr, but also highlight the efficacy of tunneling measurements as a sensitive method for probing magnetic order in van der Waals materials.

关键词： Van der Waals forces

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Fractal photonic anomalous Floquet topologicalinsulators to generate multiple quantum chiraledge states

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Light(Science & Applications) 2023年第11期12卷 2498-2507页

作者： Meng Li Chu Li Linyu Yan Qiang Li Qihuang Gong Yan Li State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Frontiers Science Center for Nano-Optoelectronics Peking UniversityBeijing 100871China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuanShanxi 030006China Hefei National Laboratory Hefei 230088China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China

Anomalous Floquet topological insulators with vanishing Chern numbers but supporting chiral edge modes are attracting more and more *** the existing anomalous Floquet topological insulators usually support only one kind of chiral edge mode even at a large lattice size,they are unscalable and unapplicable for multistate topological quantum ***,fractal topological insulators with self-similarity have been explored to support more nontrivial ***,we demonstrate the first experimental realization of fractal photonic anomalous Floquet topological insulators based on dual Sierpinski carpet consisting of directional couplers using the femtosecond laser direct *** fabricated lattices support much more kinds of chiral edge states with fewer waveguides and enable perfect hopping of quantum states with near unit transfer *** of zero-dimensional bound modes for quantum state transport in previous laser direct-written topological insulators,we generate multiple propagating single-photon chiral edge states in the fractal lattice and observe high-visibility quantum *** suggest the successful realization of highly indistinguishable single-photon chiral edge states,which can be applied in various quantum *** work provides the potential for enhancing the multi-fold manipulation of quantum states,enlarging the encodable quantum information capacity in a single lattice via high-dimensional encoding and many other fractal applications.

关键词： topological quantum chiral

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Taming Brillouin Optomechanics Using Supermode Microresonators

Taming Brillouin Optomechanics Using Supermode Microresonato...

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2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023

作者： Wang, Min Hu, Zhi-Gang Lao, Chenghao Liu, Wenjing Yang, Qi-Fan Li, Bei-Bei Institute of Physics Chinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Beijing China Peking University State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics Beijing China

We have designed and fabricated a supermode microresonstor to enhance Brillouin optomechanical coupling, and realized both phonon lasing and optomechanical strong coupling. This system exhibits a single-photon optomec... 详细信息

ISBN: (纸本)9798350312614

关键词： Brillouin optomechanics phonon lasing strong coupling supermode microcovities

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基于低浓度掺杂TTF-HLCT一体化分子提供的多重激子循环通道增强深蓝光OLED的稳定性

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Science China Materials 2024年第7期67卷 2161-2168页

作者：唐振宇龚乐帆郭浩清杨爽罗骏唐荣肖静张震曲波陈志坚肖立新 State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China College of Physics and Electronic Engineering Taishan UniversityTaian 271000China Key Laboratory of Advanced Display and System Applications Ministry of EducationShanghai UniversityShanghai 200072China

目前,商用的深蓝有机发光二极管(OLED)使用的三重态-三重态融合(TTF)型发光材料只能捕获50%的三重态(T_(1))激子,导致其器件效率较低.基于窄带蓝色发射体的热激活延迟荧光(TADF)和超荧光策略可以实现接近100%的激子利用率,然而,在发射层... 详细信息

目前,商用的深蓝有机发光二极管(OLED)使用的三重态-三重态融合(TTF)型发光材料只能捕获50%的三重态(T_(1))激子,导致其器件效率较低.基于窄带蓝色发射体的热激活延迟荧光(TADF)和超荧光策略可以实现接近100%的激子利用率,然而,在发射层(EML)中停留的高能量T_(1)激子通常会导致不可避免的分子降解,从而限制了器件的使用寿命.为了解决这一问题,本文研究了一种TTF-杂化局域-电荷转移态(HLCT)一体化分子,旨在通过多个激子回收通道降低EML内T_(1)激子的密度,从而提高高效深蓝OLED的稳定性.通过TTF过程回收T_(1)激子,通过HLCT过程利用高能三重态(Tn)激子,可以提高EML中三重态激子的利用率.此外,低浓度掺杂的TTF-HLCT分子在TADF体系中可以减轻T_(1)激子猝灭造成的效率损失.最后,实现了外量子效率(EQE)为25.9%、CIE为(0.131,0.050)、蓝光指数(CE由CIEy校准)为312 cd A^(−1) CIE_(y)^(−1)的顶发射OLED,并且其寿命T90@1000 cd m^(−2)从0.5小时延长到6.1小时.本工作揭示了低浓度TTF-HLCT分子掺杂的潜力,作为一种可行的解决方案,可以最大限度地减少效率猝灭,并解决蓝光OLED的稳定性问题.

关键词： organic light-emitting diode stability multiple ex-citon recycling channels deep blue emission TTF-HLCT

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On the Onsager-Casimir reciprocal relations in a tilted Weyl semimetal

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Chinese physics B 2022年第9期31卷 123-127页

作者： Bingyan Jiang Jiaji Zhao Lujunyu Wang Ran Bi Juewen Fan Zhilin Li Xiaosong Wu State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Frontiers Science Center for Nano-optoelectronicsPeking UniversityBeijing 100871China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Collaborative Innovation Center of Quantum Matter Beijing 100871China

The Onsager-Casimir reciprocal relations are a fundamental symmetry of nonequilibrium statistical *** we study an unusual chirality-dependent Hall effect in a tilted Weyl semimetal Co_(3)Sn_(2)S_(2) with broken time-reversal *** is confirmed that the reciprocal relations are *** two Berry curvature effects,an anomalous velocity and a chiral chemical potential,contribute to the observed Hall effect,the reciprocal relations suggest their intriguing connection.

关键词： Onsager-Casimir relations tilted Weyl semimetal chirality-dependent Hall effect

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Focus on perovskite emitters in blue light-emitting diodes

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Light(Science & Applications) 2023年第8期12卷 1566-1582页

作者： Xiaoyu Yang Li Ma Maotao Yu Hao-Hsin Chen Yongqiang Ji An Hu Qixuan Zhong Xiaohan Jia Yanju Wang Yuzhuo Zhang Rui Zhu Xinqiang Wang Changjun Lu Leyard Optoelectronic Co. Ltd100091 BeijingChina State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of PhysicsFrontiers Science Center for Nano-optoelectronics&Collaborative Innovation Center of Quantum MatterPeking University100871 BeijingChina State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology100029 BeijingChina Peking University Yangtze Delta Institute of Optoelectronics 226010 NantongJiangsuChina

Blue perovskite light-emitting diodes(PeLEDs)are essential in pixels of perovskite displays,while their progress lags far behind their red and green ***,we focus on recent advances of blue PeLEDs and systematically review the noteworthy strategies,which are categorized into compositional engineering,dimensional control,and size confinement,on optimizing microstructures,energy landscapes,and charge behaviors of wide-bandgap perovskite emitters(bandgap>2.5 eV).Moreover,the stability of perovskite blue emitters and related devices is *** the end,we propose a technical roadmap for the fabrication of state-of-the-art blue PeLEDs to chase and achieve comparable performance with the other two primary-color devices.

关键词： emitter diodes Focus

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Watts-level ultraviolet-CLED integrated light sources for efficient surface and air sterilization

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Journal of Semiconductors 2022年第7期43卷 61-67页

作者： Wei Luo Tai Li Yongde Li Houjin Wang Ye Yuan Shangfeng Liu Weiyun Wang Qi Wang Junjie Kang Xinqiang Wang Songshan Lake Materials Laboratory Dongguan 523808China State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of Physics Nano-Optoelectronics Frontier Center of Ministry of EducationPeking UniversityBeijing 100871China Dongguan Institute of Opto-Electronics Peking UniversityDongguan 523808China

With the epidemic of the coronavirus disease(COVID-19) infection, AlGaN-based ultraviolet-C light emitting diodes(UVC-LEDs) have attracted widespread attention for their sterilization application. However, the sterilization characters of high power integrated light sources(ILSs) haven’t been widely investigated before utilizing in public sanitary security. In this work,by integrating up to 195 UVC-LED chips, high power UVC-LED ILSs with a light output power(LOP) of 1.88 W were demonstrated. The UVC-LED ILSs were verified to have efficient and rapid sterilization capability, which have achieved more than99.9% inactivation rate of several common pathogenic microorganisms within 1 s. In addition, the corresponding air sterilization module based on them was also demonstrated to kill more than 97% of Staphylococcus albus in the air of 20 m3 confined room within 30 min. This work demonstrates excellent sterilization ability of UVC-LED ILSs with high LOP, revealing great potential of UVC-LEDs in sterilization applications in the future.

关键词： ultraviolet-C LED integrated light source surface sterilization air sterilization

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