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point defect Phenomena of Crystalline Structure in Some Common Structural Materials

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Chinese Journal of Structural Chemistry 2005年第9期24卷 1066-1072页

作者：阮玉忠吴任平于岩 College of Materials Science and Engineering Fuzhou University Fujian 350002 China

The existence and its movement rule of crystalline structure defect are closely related to the diffusion, solid phase reaction, sintering, phase transformation as well as the physical and chemical properties of materials. point defect theory has been widely applied in material mineralization research, unfavorable transformation controlling, material modification, the research and development of new materials and so on. point defect theory is one of the important theories for new material research and development. Herein we mainly discuss the application of point defect theory in some structural material researches.

关键词： crystalline structure point defect solid solution structural material

point defect determination by photoluminescence and capacitance-voltage characterization in a GaN terahertz Gunn diode

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Chinese Physics B 2013年第8期22卷 563-567页

作者：李亮杨林安周小伟张进成郝跃 School of Microelectronics Key Laboratory of Wide Bandgap Semiconductor Materials and Devices of Ministry of EducationXidian University

Photoluminescence （PL） measurement is used to study the point defect distribution in a GaN terahertz Gunn diode, which is able to the degrade high-field transport characteristic during further device operation. PL, secondary ion mass spectroscopy （SIMS）, transmission electron microscope （TEM）, and capacitance-voltage （C-V） measurements are used to discuss the origin of point defects responsible for the yellow luminescence in structures. The point defect densities of about 1011 cm-2 in structures are extracted by analysis of C-V characterization. After thermal annealing treatment, diminishments of point defect densities in structures are efficiently demonstrated by PL and C-V results.

关键词： GaN terahertz Gunn diode point defect photoluminescence capacitance-voltage

point defect states of a hollow cylinder in two-dimensional phononic crystal

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Chinese Physics B 2012年第6期21卷 324-328页

作者：高晓薇陈世波陈建兵郑勤红杨海 Physics Department Kunming University Department of Physics Yunnan Normal University Department of Information Management Yunnan Normal University

point defect states in two-dimensional phononic crystal of a hollow mercury cylinder in a water host are studied. An improved plane expansion method combined with the supercell technique is used to calculate the band gaps and the pressure distribution at the defect position. The sonic pressure of defect modes shows that the waves are localized at or near the defect. As the filing fraction increases, more defect modes appear in the band gaps.

关键词： phononic crystal point defect cavity defect hollow cylinder

point defect Engineering Boosting the Thermoelectric Properties of Layered 122 Zintl Compounds

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Chinese Journal of Structural Chemistry 2020年第5期39卷 815-820页

作者： GUO Kai HUO Hao-Jie LUO Jun School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai 200444China

The layered 122 Zintl compounds have become an intriguing class of thermoelectric materials due to the promising electronic transport properties and inherently low thermal conductivity,showing the typical characteristics of"phonon-glass electron-crystal".Owing to the unprecedented performance tunability,the thermoelectric properties of the layered-structure compounds are completive with some traditional thermoelectric *** defects involving vacancy,aliovalent doping and equivalent alloying atoms have been introduced to further enhance the thermoelectric *** review emphasizes the effects of various point defects on the thermoelectric parameters,and provides perspective on the strategies for increasing the thermoelectric figure of merit zT,which are believed to be applicable for improving the thermoelectric properties of many other compounds.

关键词： layered structure 122 Zintl phase point defect orbital alignment phonon scattering thermoelectric properties

Enhanced thermoelectric performance of CoSbS_(0.85)Se_(0.15) by point defect

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Rare Metals 2018年第4期37卷 326-332页

作者： Shan-Shan Zhang Ding-Feng Yang Nusrat Shaheen Xing-Chen Shen Dan-Dan Xie Yan-Ci Yan Xu Lu Xiao-Yuan Zhou Department of Applied Physics Chongqing University Institute of Microstructure and Properties of Advanced Materials Beijing University of Technology

In this study, we report the effect of Zn doping on the thermoelectric properties of CO1-xZnxSbS0.85Se0.15 solid solutions （x = 0, 0.02, 0.05, 0.08）. The results show the dimensionless figure of merit （zT） increases from 0.17 to 0.34 at 875 K for Co0.95Zn0.05SbS0.85Se0.15 sample, due to the noticeable decrease in the lattice thermal conductivity by introducing point defect, which is further confirmed by an analysis based on the Debye-Callaway- Klemens model. Meanwhile, the thermoelectric power factor is maintained at high temperatures. This work highlights the important role of point defect in improving the thermoelectric performance of CoSbS-based compounds.

关键词： CoSbS point defect Thermal conductivity Thermoelectric performance

The point defect and electronic structure of K doped LaCo_(0.9)Fe_(0.1)O_(3)perovskite with enhanced microwave absorbing ability

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Nano Research 2022年第4期15卷 3720-3728页

作者： Fan Wang Weihua Gu Jiabin Chen Yue Wu Ming Zhou Shaolong Tang Xingzhong Cao Peng Zhang Guangbin Ji College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

ABO_(3)perovskites,owning unique properties,have great research prospect in electromagnetic wave absorption ***,doping can significantly regulate the dielectric loss,whereas the magnetic loss can be *** this work,the crystal structure and electromagnetic properties can be regulated systematically by the K,Fe co-doping for LaCoO_(3)perovskites(LKCFO)under the condition of fixed F *** addition,the obtained samples show the obvious interfacial polarization effect on accounting to the small size effect,which is conducive to the effective microwave *** analyzing the evolution of the positron annihilation lifetime and the first-principles calculation of the oxygen density of states for the series of LKCFO perovskites,it is found that the charge transport characteristics will be controlled by the point defect generated by allelic *** point defect content decreases and then increases as the doping level *** prepared perovskite exhibits the lowest defect density and the largest dielectric loss capability,which indicates that the lower point defects promote electron migration and thus enhance the dielectric loss;thus,the electromagnetic wave absorption bandwidth up to 6.2 GHz is *** contrast,both insufficient and excessive K doping are detrimental to the enhancement of microwave ***,the practical application value was investigated using Computer Simulation Technology(CST)*** LKCFO-2 exhibits the smallest RCS value(below-10 dBm^(2))at almost-90°-90°with a thickness of 2 mm,providing an effective method for study excellent microwave absorption and scattering property.

关键词： microwave absorption perovskites doping effective bandwidth point defect

point defect approach to enhance the thermoelectric performance of Zintl-phase BaAgSb

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Science China Materials 2021年第10期64卷 2541-2550页

作者： Yifang Huang Chen Chen Weiming Zhang Xiaofang Li Wenhua Xue Xinyu Wang Yijie Liu Honghao Yao Zongwei Zhang Yue Chen Feng Cao Xingjun Liu Yumei Wang Qian Zhang School of Materials Science and Engineering and Institute of Materials Genome&Big DataHarbin Institute of TechnologyShenzhen 518055China Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong Kong SARChina Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Science Harbin Institute of TechnologyShenzhen 518055China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Zintl-phase compounds have great potential in thermoelectric applications owing to their“phonon glasselectron crystal”(PGEC)*** this paper,a new Zintlphase thermoelectric material Ba Ag Sb is *** deficiency increased the carrier concentration,and then suppressed the intrinsic *** peak ZT value of Ba_(0.98)Ag Sb reached~0.56 at 773 ***,Eu alloying at Ba site not only lowered the lattice thermal conductivity by inducing point-defect scattering,but also improved the electrical properties by increasing the carrier ***,a peak ZT of~0.73 was achieved in Ba_(0.78)Eu_(0.2)Ag Sb.

关键词： thermoelectric Zintl phase point defect isoelectronic alloying

A review of solute-point defect interactions in vanadium and its alloys: first-principles modeling and simulation

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Tungsten 2021年第1期3卷 38-57页

作者： Peng-Bo Zhang Ji-Jun Zhao Ting-Ting Zou Rui-Huan Li Peng-Fei Zheng Ji-Ming Chen School of Science Dalian Maritime UniversityDalian 116026China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)Dalian University of TechnologyDalian 116024China Information Science and Technology College Dalian Maritime UniversityDalian 116026China Institute of Mold Technology Changzhou Vocational Institute of Mechatronic TechnologyChangzhou 213164China Southwestern Institute of Physics Chengdu 610041China

Vanadium alloys are the promising first wall and blanket materials for fusion *** amounts of helium(He)and hydrogen(H)impurities are produced inside the materials along with irradiation defects under neutron irradiation,leading to bubble formation and microstructure changes,which will degrade the thermal and mechanical properties of vanadium *** microstructure changes of materials are influenced by the interactions of point defects with solute ***,first-principles calculations are intensively performed to elucidate these interactions,clustering,and dissolution,which can provide valuable information for the design of high-performance anti-irradiation *** paper reviews the recent findings of the interactions of point defects(vacancies,self-interstitial atoms)with substitutional solutes and interstitial solutes(C,O,N,H,and He)as well as their clusters in vanadium and its alloys from first-principles calculations.

关键词： Solute atom point defect Radiation damage H and He effect Vanadium alloys Density functional theory

point defect STATES OF BENDING WAVES IN PHONONIC CRYSTAL THIN PLATES

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POINT DEFECT STATES OF BENDING WAVES IN PHONONIC CRYSTAL THI...