检索结果-南通市图书馆

Chinese Physics B 2022年第1期31卷 516-523页

作者： Huihui He shenyuan yang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China

Using first-principles calculations based on density functional theory,we have systematically studied the influence of in-plane lattice constant and thickness of slabs on the concentration and distribution of two-dimensional hole gas(2 DHG)in AlN/GaN *** show that the increase of in-plane lattice constant would increase the concentration of 2 DHG at interfaces and decrease the valence band offset,which may lead to a leak of *** the thickness of AlN and/or decreasing the thickness of GaN would remarkably strengthen the internal field in GaN layer,resulting in better confinement of 2 DHG at AlN/GaN ***,a moderate larger in-plane lattice constant and thicker AlN layer could improve the concentration and confinement of 2 DHG at AlN/GaN *** study could serve as a guide to control the properties of 2 DHG at Ⅲ-nitride interfaces and help to optimize the performance of p-type nitride-based devices.

关键词： two-dimensional hole gas III-nitride interfaces polarization first-principles calculations

Antiferromagnetic-ferromagnetic transition in zigzag graphene nanoribbons induced by substitutional doping

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第11期27卷 568-574页

作者： shenyuan yang Jing Li Shu-Shen Li State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Microelectronics University of Chinese Academy of SciencesBeijing l 01408China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 101408China Synergetic Innovation Center of Quantum Intbrmation and Quantum Physics University of Science and Technology of ChinaHefei 230026China

Using first-principles calculations based on density functional theory,we show that the ground state of zigzag-edged graphene nanoribbons(ZGNRs)can be transformed from antiferromagnetic(AFM)order to ferromagnetic(FM)order by changing the substitutional sites of N or B *** AFM–FM transition induced by substitutional sites is found to be a consequence of the competition between the edge and bulk *** energy sequence of the edge and bulk states near the Fermi level is reversed in the AFM and FM *** the dopant is substituted near the edge of the ribbon,the extra charge from the dopant is energetically favorable to occupy the edge states in AFM *** the dopant is substituted near the center,the extra charge is energetically favorable to occupy the bulk states in FM *** substrate with weak interaction is necessary to maintain the magnetic properties of the doped *** study can serve as a guide to synthesize graphene nanostructures with stable FM order for future applications to spintronic devices.

关键词： graphene nanoribbon substitutional doping magnetic order first-principles calculation

The effect of Bi composition on the electrical properties of InP1-xBix

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 82-85页

作者： GuanNan Wei Xing Dai Qi Feng WenGang Luo Yiyang Li Kai Wang LiYao Zhang WenWu Pan ShuMin Wang shenyuan yang KaiYou Wang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China State Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China State Key Laboratory of Functional Materials for lnformatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

III-V Semiconductors containing a small amount of Bi, known as dilute bismides, have attracted great interest in recent years, due to the large band-gap reduction and other unique properties [1,2]. Previous studies have been pri- marily focused on the growth and optical properties of the GaAs-based bismuthides [3], while the properties of other dilute bismides are less well understood. Berding et al. [4] theoretically predicted that InPBi is expected to be an attractive candidate for narrow-gap applications. Experimentally, the InPBi alloy with good single crystal quality has been successfully synthesized recently and exhibits strong and broad photoluminescence at room temperature [5,6]. However, the electric transport characteristics of the InPBi alloy are poorly understood. In this work, we systematically investigate the effect of Bi incorporation on electric transport properties of the InP1-xBix alloys.

关键词： In Bi Ta The effect of Bi composition on the electrical properties of InP x)Bi_x

Graphene-driving strain engineering to enable strain-free epitaxy of AlN film for deep ultraviolet light-emitting diode

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2022年第5期11卷 808-819页

作者： Hongliang Chang Zhetong Liu shenyuan yang Yaqi Gao Jingyuan Shan Bingyao Liu Jingyu Sun Zhaolong Chen Jianchang Yan Zhiqiang Liu Junxi Wang Peng Gao Jinmin Li Zhongfan Liu Tongbo Wei Research and Development Center for Semiconductor Lighting Technology Institute of SemiconductorsChinese Academy of Sciences100083 BeijingChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences100049 BeijingChina Center for Nanochemistry(CNC) Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University100871 BeijingChina Electron Microscopy Laboratory and International Center for Quantum MaterialsSchool of PhysicsPeking University100871 BeijingChina Beijing graphene institute(BGI) 100095 BeijingChina Academy for Advanced Interdisciplinary Studies Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced MaterialsPeking University100871 BeijingChina State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences100083 BeijingChina

The energy-efficient deep ultraviolet(DUV)optoelectronic devices suffer from critical issues associated with the poor quality and large strain of nitride material system caused by the inherent mismatch of *** this work,we have prepared the strain-free AlN film with low dislocation density(DD)by graphene(Gr)-driving strain-pre-store engineering and a unique mechanism of strain-relaxation in quasi-van der Waals(QvdW)epitaxy is *** DD in AlN epilayer with Gr exhibits an anomalous sawtooth-like evolution during the whole epitaxy *** can help to enable the annihilation of the dislocations originated from the interface between AlN and Gr/sapphire by impelling a lateral two-dimensional growth ***,it can induce AlN epilayer to pre-store sufficient tensile strain during the early growth stage and thus compensate the compressive strain caused by ***,the low-strain state of the DUV light-emitting diode(DUV-LED)epitaxial structure is realized on the strain-free AlN template with ***,the DUV-LED with Gr demonstrate 2.1 times enhancement of light output power and a better stability of luminous wavelength compared to that on bare *** in-depth understanding of this work reveals diverse beneficial impacts of Gr on nitride growth and provides a novel strategy of relaxing the vital requirements of hetero-mismatch in conventional heteroepitaxy.

关键词： sapphire diode strain

A first-principles study on remote van der Waals epitaxy through a graphene monolayer on semiconductor substrates

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第6期32卷 466-475页

作者：侯锐杨身园 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-electronic Technology University of Chinese Academy of SciencesBeijing 100049China

To investigate the mechanism of remote epitaxy, where the overlayer can follow the same crystalline structure as the underlying semiconductor substrate through a thin two-dimensional interlayer, we systematically study the potential fluctuations of graphene covered Si, Ga As, and Ga N substrates from first-principles. We find that the uneven semiconductor surface, the distorted graphene, and the non-uniform interface charge transfer make significant contributions to the potential fluctuation. The semiconductor substrate with different surface reconstructions and orientations will generate different potential fluctuations through the graphene interlayer. We also calculate and compare the adsorption of adatoms on graphene covered substrates. The adsorption energies of adatoms not only depend on their distances to the underlying semiconductor surface, but are also sensitive to the direction of the charge transfer at the graphene/substrate interface. Changing the semiconductor reconstruction or orientation could even reverse the order of the adsorption energies of cation and anion adatoms by reversing the interface charge transfer direction, leading to a change in the growth orientation of the *** study improves the understanding of the mechanism of remote epitaxy, and reveals that it is possible to control the initial nucleation and orientation of overlayers by changing the semiconductor reconstructions and/or orientations in remote epitaxy.

关键词： interface adsorption remote epitaxy first-principles

Two-dimensional material-assisted remote epitaxy and van der Waals epitaxy: a review

在线全文

学校读者我要写书评

暂无评论

National Science Open 2023年第4期2卷 86-102页

作者： Zhetong Liu Bingyao Liu Zhaolong Chen shenyuan yang Zhiqiang Liu Tongbo Wei Peng Gao Zhongfan Liu Electron Microscopy Laboratory and International Center for Quantum MaterialsSchool of PhysicsPeking UniversityBeijing 100871China Beijing Graphene Institute(BGI) Beijing 100095China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China Center for Nanochemistry(CNC) Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Institute for Functional Intelligent Materials National University of SingaporeSingapore 117575Singapore State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Research and Development Center for Semiconductor Lighting Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Collaborative Innovation Center of Quantum Matter Beijing 100871China

Heteroepitaxy can reduce the cost and widen the application range of semiconductor film synthesis and device ***,the lattice and thermal expansion coefficient mismatches between epilayers and substrates limit the improvement of crystal quality and device ***-dimensional(2D)material-assisted heteroepitaxy offers an effective solution to these *** weak interaction at the interface between films and substrates facilitates the subsequent exfoliation and transfer of epilayer for the fabrication of flexible or high-power ***,we summarize the modes of 2D material-assisted epitaxy,which can be classified into remote epitaxy,pinhole epitaxy and van der Waals epitaxy based on the interfacial interaction between the epilayers and ***,we discuss in detail the improved crystal quality and functional applications,such as flexible devices,wavelength-modulated optoelectronic devices,and thermal management in high-power ***,we highlight the challenges and prospects of 2D material-assisted epitaxy,providing roadmaps for lateral research and semiconductor production.

关键词： graphene 2D materials heteroepitaxy remote epitaxy pinhole epitaxy van der Waals epitaxy

在线全文

学校读者我要写书评

暂无评论

一种改进的证据合成规则

计算机工程 2006年第23期32卷 7-9页

作者：蒲书缙杨雷杨莘元胡炜薇哈尔滨工程大学信息与通信工程学院哈尔滨150001

就D-S证据合成规则对于冲突证据合成存在的不足,不少学者基于证据冲突概率再分配思想,提出了相应的修正证据合成规则。针对这些修正合成规则的不足,提出了一种改进的合成规则,该规则在综合考虑证据源可信度和证据支持度的基础上,分析证... 详细信息

就D-S证据合成规则对于冲突证据合成存在的不足,不少学者基于证据冲突概率再分配思想,提出了相应的修正证据合成规则。针对这些修正合成规则的不足,提出了一种改进的合成规则,该规则在综合考虑证据源可信度和证据支持度的基础上,分析证据集的有效性,合理地实现信息融合。数值实验结果表明,新的合成规则不仅克服了现有规则的不足,而且其结果向合理性方向收敛度好,提高了系统的鲁棒性。

关键词：证据理论合成规则证据冲突证据有效性数据融合

在线全文

学校读者我要写书评

暂无评论

相位调制水声高速通信中的一种空间滤波算法

声学学报 2006年第1期31卷 79-84页

作者：刘云涛蔡惠智杨莘元中国科学院声学研究所北京100080

提出了一种智能天线技术与空时联合判决反馈均衡器相结合的空间滤波算法。实现方法是水下通信系统采用水听器阵列接收,进行多波束智能天线算法处理,得到多路空间滤波后的信号,再经过空时联合判决反馈均衡处理。该算法已应用于在实际的... 详细信息

提出了一种智能天线技术与空时联合判决反馈均衡器相结合的空间滤波算法。实现方法是水下通信系统采用水听器阵列接收,进行多波束智能天线算法处理,得到多路空间滤波后的信号,再经过空时联合判决反馈均衡处理。该算法已应用于在实际的水下正交相移键控调制高速水声通信系统中,在相同条件下的湖水试验中,与传统的空间分集算法进行了比较,获得的误码率分别为2．9×10-3和8．62×10-2,多组试验结果表明该算法有效抑制了水下多径干扰的影响,获得了与空间分集算法相比低十倍的误码率。

关键词：滤波算法空间滤波高速通信相位调制水声判决反馈均衡器多波束智能天线智能天线技术通信系统空间分集

在线全文

学校读者我要写书评

暂无评论

卫星导航信号波形性能分析

弹箭与制导学报 2010年第4期30卷 61-64页

作者：王垚杨莘元蔚保国哈尔滨工程大学信息与通信工程学院哈尔滨150001 河北省卫星导航技术与装备工程技术研究中心石家庄050081

针对不同的伪码波形对码跟踪环的性能影响存在差异，推导了卫星导航信号脉冲波形的性能评估准则。准则从两方面考虑，一是码跟踪误差，一是抗多径性能。仿真分析了几种典型波形的信号，得出在相同条件下，线性偏移副载波信号（LOC）具... 详细信息

针对不同的伪码波形对码跟踪环的性能影响存在差异，推导了卫星导航信号脉冲波形的性能评估准则。准则从两方面考虑，一是码跟踪误差，一是抗多径性能。仿真分析了几种典型波形的信号，得出在相同条件下，线性偏移副载波信号（LOC）具有最小的码跟踪误差下限，二进制偏移副载波信号（BOC）具有最小的多径误差包络下限。具有较优码跟踪误差下限的信号不一定具有较好的抗多径能力，所以针对不同的应用要考虑两者的均衡。

关键词： GNSS 信号波形修正卡拉美罗界码跟踪误差抗多径 BOC

在线全文

学校读者我要写书评

暂无评论

新型陆基无线电导航系统所需辐射功率计算

弹箭与制导学报 2006年第S1期26卷 211-213页

作者：刘楠姜弢杨莘元哈尔滨工程大学信息与通信工程学院哈尔滨150001

提出了采用类似于GPS的伪噪声相位编码信号体制,构成一个具有较高定位精度的新型陆基无线电导航系统,系统面临的主要新问题是必须采用地波传播方式,传播衰减大,而大气噪声又成为主要的干扰因素。就特定海域分析和计算了大气噪声的功率... 详细信息

提出了采用类似于GPS的伪噪声相位编码信号体制,构成一个具有较高定位精度的新型陆基无线电导航系统,系统面临的主要新问题是必须采用地波传播方式,传播衰减大,而大气噪声又成为主要的干扰因素。就特定海域分析和计算了大气噪声的功率谱密度,同时计算了在保证较高测量精度条件下所需要的最低场强,继而给出了无线电导航系统所需辐射功率的计算方法。通过实例表明,构成一个工作距离为1000km的新型陆基无线电导航系统在技术上是可行的。

关键词： GPS 无线电导航大气热噪声辐射功率