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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 applications.Here,a desorption-tailoring strategy is proposed to juggle the carrier concentration and transport.Specific 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 approach.The 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 desorption.More 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 power.This 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

微单倍型遗传标记的研究进展及在动物保护上的应用潜力

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野生动物学报 2024年第1期45卷 193-203页

作者：谢大鑫许蔚沈富军张修月四川大学生命科学学院生物资源与生态环境教育部重点实验室成都610065 成都大熊猫繁育研究基地成都610081 四川省濒危野生动物保护生物学重点实验室成都610081

新型遗传标记微单倍型,凭借高稳定性、无“stutter”峰干扰、高多态性、短扩增片段和SNP位点需求量少等显著优势逐渐受到法医物证学、种群遗传学等领域研究人员的关注,并在亲缘关系分析与亲子鉴定方面得到较好应用。本文逐一综述了微单... 详细信息

新型遗传标记微单倍型,凭借高稳定性、无“stutter”峰干扰、高多态性、短扩增片段和SNP位点需求量少等显著优势逐渐受到法医物证学、种群遗传学等领域研究人员的关注,并在亲缘关系分析与亲子鉴定方面得到较好应用。本文逐一综述了微单倍型的发展、命名规则与筛选标准等,回顾了微单倍型数据获取、分析与检测的研究进展,首次对微卫星、SNP和微单倍型3种遗传标记进行了全面比较,并介绍了微单倍型遗传标记在动物学领域的应用潜力及面临的挑战与机遇,期冀为相关研究提供参考。

关键词：微单倍型遗传标记发展演变动物学应用潜力

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以二氢苊骨架构建的深蓝光有机电致发光材料

高等学校化学学报 2024年第1期45卷 43-52页

作者：王妍张富俊张校宇徐佳惠童碧海陈平孔辉安徽工业大学冶金与资源学院马鞍山243002 烟台大学物理与电子信息学院山东省高校光电子功能材料与光电子器件特色实验室烟台264005 南京大学配位化学国家重点实验室南京210023

合成了4种在二氢苊骨架上连接咔唑或三苯胺电子给体和氰基苯电子受体的发光材料,考察了电子给体连接方式及种类对材料光电性能的影响.目标化合物的单晶结构分析结果显示,位阻导致给/受体与二氢苊骨架不共平面,从而降低了共轭程度,消除... 详细信息

合成了4种在二氢苊骨架上连接咔唑或三苯胺电子给体和氰基苯电子受体的发光材料,考察了电子给体连接方式及种类对材料光电性能的影响.目标化合物的单晶结构分析结果显示,位阻导致给/受体与二氢苊骨架不共平面,从而降低了共轭程度,消除了分子间π⁃π堆积作用,分子间依靠大量的C—H…π分子间相互作用稳定,只有3CzAB存在分子内π⁃π堆积作用.4种化合物均具有非常高的热稳定性,5%热失重温度(Td,5%)高于343℃.这些材料在PMMA薄膜中的发光均为深蓝光发射(403~432 nm),光致发光效率高(0.60~0.94),荧光寿命为5.4~8.6 ns.电致发光性能测试结果表明,以三苯胺为给体的材料PaAB的电致发光性能最佳,最大亮度可达2427 cd/m,峰值电流效率、功率效率和外量子效率分别为2.43 cd/A,1.53 lm/W和1.58%,色坐标(CIEx,y)为(0.15,0.09),为深蓝光发射.

关键词：深蓝光分子有机电致发光二氢苊荧光

稀土La掺杂TiO_(2)纳米纤维高响应光催化降解染料研究

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功能材料 2024年第3期55卷 3159-3164页

作者：葛烨倩徐佳琦曹琪张霞霞王益峰许福军东华大学纺织学院上海201620 绍兴文理学院纺织服装学院浙江绍兴312000 浙江富润印染有限公司浙江绍兴312000

为了提高TiO_(2)光催化性能,并研究金属离子掺杂对TiO_(2)光催化性能的影响,采用静电纺丝技术和煅烧工艺制备稀土元素La掺杂TiO_(2)无机纳米纤维膜,通过SEM、XRD、FT-IR、TG测试对材料的形貌、结构进行表征,以亚甲基蓝为靶向降解剂,进... 详细信息

为了提高TiO_(2)光催化性能,并研究金属离子掺杂对TiO_(2)光催化性能的影响,采用静电纺丝技术和煅烧工艺制备稀土元素La掺杂TiO_(2)无机纳米纤维膜,通过SEM、XRD、FT-IR、TG测试对材料的形貌、结构进行表征,以亚甲基蓝为靶向降解剂,进一步深入研究La^(3+)改性TiO_(2)光催化氧化降解染料的机理。结果表明,当染料浓度为10 mg/L,La^(3+)掺杂改性纳米TiO_(2)纤维的浓度为15 mg/10 mL条件下,催化10 min的降解率为63.41%,催化70 min的降解率即可达到99.87%,比未掺杂TiO_(2)纳米纤维的降解率提高了6.36%,可见,La^(3+)的掺杂提高了TiO_(2)光催化降解速率,所需要的时间减少了。

关键词： La^(3+)掺杂 TiO_(2) 光催化剂染料降解

Infrared stimulated emission with an ultralow threshold from low-dislocation-density InN films grown on a vicinal GaN substrate

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Fundamental Research 2022年第5期2卷 794-798页

作者： Huapeng Liu Bowen Sheng Tao Wang Konstantin Kudryavtsev Artem Yablonskiy Jiaqi Wei Ali Imran Zhaoying Chen Ping Wang Xiantong Zheng Renchun Tao xuelin Yang fujun xu Weikun Ge Bo Shen Boris Andreev Xinqiang Wang State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China Institute for Physics of Microstructures Russian Academy of SciencesNizhny Novgorod 603950Russia Collaborative Innovation Center of Quantum Matter Beijing 100871China

Near-infrared stimulated emission from a high-quality InN layer under optical pumping was observed with a threshold excitation power density of 0.3 and 4 kW cm^(−2) at T=8 and 77 K,respectively.To achieve such a low threshold power density,vicinal GaN substrates were used to reduce the edge-component threading dislocation(ETD)density of the InN film.Cross-sectional transmission electron microscopy images reveal that the annihilation of ETDs can be divided into two steps,and the ETD density can be reduced to approximately 5×10^(8) cm^(−2) near the surface of the 5-μm-thick film.The well-resolved phonon replica of the band-to-band emission in the photoluminescence spectra at 9 K confirm the high quality of the InN film.As a result,the feasibility of InN-based photonic structures and the underlying physics of their growth and emission properties are demonstrated.

关键词： InN Stimulated emission Vicinal substrate Phonon replica Molecular beam epitaxy

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青藏铁路接触网异型桩基抗冻拔模型试验研究

西南交通大学学报 2024年第3期59卷 677-684页

作者：周亚龙王旭蒋代军刘德仁何菲晏昌牛富俊兰州交通大学土木工程学院甘肃兰州730070 兰州交通大学甘肃省道路桥梁与地下工程重点实验室甘肃兰州730070 西北生态资源环境研究院甘肃兰州730000

保证接触网支柱桩基础的冻拔稳定性是青藏铁路格拉段电气化改造工程建设中的关键问题之一,为研究不同截面形式桩(等截面圆形桩Z1、直锥柱形桩Z2及曲锥柱形桩Z3)的抗冻拔性能,以青藏线路基填料为试验土体,进行3个冻融循环的室内模型试验... 详细信息

保证接触网支柱桩基础的冻拔稳定性是青藏铁路格拉段电气化改造工程建设中的关键问题之一,为研究不同截面形式桩(等截面圆形桩Z1、直锥柱形桩Z2及曲锥柱形桩Z3)的抗冻拔性能,以青藏线路基填料为试验土体,进行3个冻融循环的室内模型试验,得到冻融作用下接触网支柱桩基础的地温、桩顶位移及桩身应力的分布规律.试验结果表明:路基体的冻结(融化)是二维冻结(融化),接触网支柱桩基础附近的冻结深度约为30 cm;路肩处土体的竖向冻胀位移为4.30 mm,Z1的竖向冻拔量为0.26 mm,Z2与Z3的竖向冻拔量分别为Z1的46%、58%,3根桩的桩顶均产生约0.1 mm的水平位移;冻结过程中桩基整体受拉,冻深附近桩身轴力最大;切向冻胀应力的最大值出现在地表附近,曲锥柱形桩切向冻胀总力最小,抗冻拔效果最好.

关键词：多年冻土接触网支柱桩基础异型桩模型试验冻融作用冻拔特性

Review on the Progress of AlGaN-based Ultraviolet Light-Emitting Diodes

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Fundamental Research 2021年第6期1卷 717-734页

作者： Yuxuan Chen Jianwei Ben fujun xu Jinchai Li Yang Chen Xiaojuan Sun 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 State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Fujian Key Laboratory of Semiconductor Materials and Applications CI Center for OSEDCollege of Physical Science and TechnologyXiamen UniversityXiamen 361005China

AlGaN-based materials have exhibited considerable potential for fabricating ultraviolet(UV)light-emitting diodes(LEDs)owing to their direct,wide,and adjustable energy bandgap.AlGaN-based devices have extensive appli-cability owing to their stable physico-chemical properties.With decades of research effort,significant progress has been achieved in enhancing the working efficiency of AlGaN-based LEDs by optimizing the crystalline qual-ity,doping efficiency,and device design.In this review,methods to obtain high-quality AlGaN-based materials,achieve high doping efficiency,and design UV-LED structures are summarized and discussed.Finally,the issues that need to be addressed in AlGaN-based UV-LED devices are highlighted.

关键词： AlGaN Growth of AlGaN-based material Doping UV-LED

基于2-氰基吡啶电子受体的热激活延迟荧光材料

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高等学校化学学报 2024年第3期45卷 73-83页

作者：汪青松张富俊徐慧慧陈思浛张千峰童碧海陈平孔辉安徽工业大学冶金工程学院分子工程与应用化学研究所马鞍山243002 烟台大学物理与电子信息学院山东省高校光电子功能材料与光电子器件特色实验室烟台264005 南京大学配位化学国家重点实验室南京210023

合成了4种以2-氰基吡啶为电子受体的发光材料,考察了不同电子给体对材料发光性能的影响.研究结果表明,化合物5-(10H-吩噻嗪-10-基)吡啶腈(PTPN)的单晶结构中,吡啶环之间的分子间氢键及吩噻嗪基团之间的C-H···π分子间相互作用使吡啶... 详细信息

合成了4种以2-氰基吡啶为电子受体的发光材料,考察了不同电子给体对材料发光性能的影响.研究结果表明,化合物5-(10H-吩噻嗪-10-基)吡啶腈(PTPN)的单晶结构中,吡啶环之间的分子间氢键及吩噻嗪基团之间的C-H···π分子间相互作用使吡啶环与噻吩基团之间形成共平面的构型,导致其发光由薄膜中的520 nm蓝移至400 nm.4种化合物在聚甲基丙烯酸甲酯(PMMA)薄膜中的发光波长在434~520 nm之间.化合物5-(10H-吩噁嗪-10-基)吡啶腈(PXPN),PTPN和5-[9,9-二甲基吖啶-10(9H)-基]吡啶腈(DAPN)的光致发光量子效率(PLQY)在0.17~0.57之间,具有热激活延迟荧光(TADF)发光性质,延迟荧光寿命在4.1~5.3μs之间,单重态/三重态能隙(ΔEST)在0.045~0.069 eV之间.化合物5-(3,6-二叔丁基-9H-咔唑-9-基)吡啶腈(BCPN)的PLQY为0.91,发光寿命为12.4 ns,为荧光发射.电致发光器件性能测试表明,4种材料均发射绿光,其中DAPN的综合器件性能最佳,掺杂器件的最大亮度可达2855 cd/m^(2),峰值电流效率(CE)、功率效率(PE)和外量子效率(EQE)分别为37.6 cd/A,12.6 lm/W和10.4%.基于化合物BCPN的器件形成了高效的电致激基复合物,器件的最大亮度可达2367 cd/m^(2),峰值CE,PE和EQE分别为29.3 cd/A,11.5 lm/W和9.4%.该研究表明,氰基吡啶受体能形成稳定的分子间氢键,可用于TADF材料的开发.

关键词：热激活延迟荧光有机电致发光氰基吡啶电子受体

Ultrathin,elastic,and self-adhesive nanofiber bio-tape:An intraoperative drug-loading module for ureteral stents with localized and controlled drug delivery properties for customized therapy

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Bioactive Materials 2022年第12期7卷 128-137页

作者： Liheng Gao Mingxi xu Wenshuo Zhao Ting Zou fujun Wang Jun Da Yiwei Wang Lu Wang Key Laboratory of Textile Science and Technology Ministry of EducationCollege of TextilesDonghua UniversityShanghai201620China Department of Urology Ninth People’s HospitalSchool of MedicineShanghai Jiaotong UniversityShanghai200011China

During the postoperative management of urinary diseases,oral or intravenous administration of drugs and implanting ureteral stents are usually required,making localized drug delivery by ureteral stent a precise and effective medication strategy.In the traditional drug loading method,the drug was premixed in the implants in production lines and the versatility of drugs was restricted.However,the complex situation in the urinary system fails the possibility of finding a“one fits all”medication plan,and the intraoperative drug-loading of implants is highly desired to support customized therapy.Here,we designed an ultrathin(8μm),elastic,and self-adhesive nanofiber bio-tape(NFBT)that can easily encapsulate drugs on the stent surface for controllable localized drug delivery.The NFBT exhibited high binding strength to a ureteral stent,a sustained release over 7 d in PBS for hydrophilic drug,and a zero-order release curve over 28 days for the hydrophobic drug nitrofurantoin(NFT).Further in vivo experiments using a porcine ureteral tract infection model demonstrated that NFBT loaded with NFT could significantly reduce the bacterial concentration in urine.The total amount of NFT delivered by the NFBT was about 2.68 wt%of the recommended dose for the systemic administration.

关键词： Intraoperative drug delivery Customized therapy Ureteral stent Urinary tract infection