共查询到20条相似文献，搜索用时 15 毫秒
1.
采用透射电子显微镜对CdZnTe晶体材料的缺陷特性进行了分析。在（111）面的透射电镜明场像中，观察到了棱柱位错环、位错墙、沉淀相、层错及倾斜的孪晶界面。应力是位错形成的主要原因，棱柱位错环的产生是由于沉淀相粒子在基体上产生错配应力；而位错网络与位错墙是两种热应力联合作用于晶体边缘的结果。晶体生长过程中，液固界面生长形态从平界面向胞状界面发展产生的沉淀相衬度不同于由于Te原子溶解度的回退产生的沉淀相衬度。CdZnTe晶体中的堆跺层错和孪晶与固液界面的稳定性相关。 相似文献
2.
Freya Johnson Frederic Rendell-Bhatti Bryan D. Esser Aisling Hussey David W. McComb Jan Zemen David Boldrin Lesley F. Cohen 《Advanced materials (Deerfield Beach, Fla.)》2024,36(27):2401180
Antiferromagnets hosting structural or magnetic order that breaks time reversal symmetry are of increasing interest for “beyond von Neumann” computing applications because the topology of their band structure allows for intrinsic physical properties, exploitable in integrated memory and logic function. One such group are the noncollinear antiferromagnets. Essential for domain manipulation is the existence of small net moments found routinely when the material is synthesized in thin film form and attributed to symmetry breaking caused by spin canting, either from the Dzyaloshinskii–Moriya interaction or from strain. Although the spin arrangement of these materials makes them highly sensitive to strain, there is little understanding about the influence of local strain fields caused by lattice defects on global properties, such as magnetization and anomalous Hall effect. This premise is investigated by examining noncollinear antiferromagnetic films that are either highly lattice mismatched or closely matched to their substrate. In either case, edge dislocation networks are generated and for the former case, these extend throughout the entire film thickness, creating large local strain fields. These strain fields allow for finite intrinsic magnetization in seemingly structurally relaxed films and influence the antiferromagnetic domain state and the intrinsic anomalous Hall effect. 相似文献
3.
Guangming Cheng Shanshan Yao Xiahan Sang Boyi Hao Dongyan Zhang Yoke Khin Yap Yong Zhu 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(6):818-824
Irradiation‐induced vacancy defects in multiwalled (MW) boron nitride nanotubes (BNNTs) are investigated via in situ high‐resolution transmission electron microscope operated at 80 kV, with a homogeneous distribution of electron beam intensity. During the irradiation triangle‐shaped vacancy defects are gradually generated in MW BNNTs under a mediate electron current density (30 A cm?2), by knocking the B atoms out. The vacancy defects grow along a well‐defined direction within a wall at the early stage as a result of the curvature induced lattice strain, and then develop wall by wall. The orientation or the growth direction of the vacancy defects can be used to identify the chirality of an individual wall. With increasing electron current density, the shape of the irradiation‐induced vacancy defects changes from regular triangle to irregular polygon. 相似文献
4.
The manner in which oxygen is incorporated into YBa2Cu3O
x
(YBCO) at 800°C for values ofx close to 6 is shown to be in the form of neutral oxygen interstitials, O
i
x
. The experimental data on which this conclusion is based are obtained from measurements of oxygen partial pressure,P(O2), as a function of compositionx and temperatureT (5.99x 6.35, 825T1120 K). The data are obtained by a solid-state electrochemical method. Other conclusions of this study include: (a) O
i
x
are noninteracting forx 6. (b) The stoichiometric composition of YBCO isx 6.0. (c) The reaction enthalpy of oxidation is 179 kJ/mol O2. (d) The Fermi level changes by –0.2 eV asx increases from 6.05 to 6.35. 相似文献
5.
Ming‐Sheng Wang Dmitri Golberg Yoshio Bando 《Advanced materials (Deerfield Beach, Fla.)》2010,22(36):4071-4075
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Amorphization is often observed during irradiation of intermetallic compounds with energetic charged particles or neutrons.
This paper discusses various mechanisms of radiation induced amorphization and also presents the results of amorphization
in Al-Mn alloys. 相似文献
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《Particulate Science and Technology》2007,25(1):21-35
Characterization of submicrometer and subnanometer size particles is essential to understanding their interactions and to developing micro- and nanostructures. Because of this importance, many advances and new developments have been made in characterization techniques for particles in this size range. Examples include neutron holography, in situ wet transmission electron microscopy, ultrafast microscopy, magnetic resonance force microscopy for imaging a single electron spin, and high-resolution X-ray crystallography of noncrystalline structures. It is now possible to completely characterize very small particles from 0.1 nm to 100 nm size. Selected recent developments are discussed. 相似文献
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王磊 《中国材料科技与设备》2014,(3):69-70,73
本文简述了使用一种新型磨料球形砂（ARSAND）替代传统喷砂磨料,对一些对表面质量要求较高并采用荧光检验的高精密铸件进行喷砂的方法。该方法可显著消除经荧光检测出现的弥散点状表面缺陷,有效降低了铸件返修率、报废率。 相似文献
15.
Alicja Bachmatiuk Jiong Zhao Sandeep Madhukar Gorantla Ignacio Guillermo Gonzalez Martinez Jerzy Wiedermann Changgu Lee Juergen Eckert Mark Hermann Rummeli 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(5):515-542
The initial isolation of graphene in 2004 spawned massive interest in this two‐dimensional pure sp2 carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State‐of‐the‐art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in‐situ investigations is also presented. 相似文献
16.
Baldev Raj 《Bulletin of Materials Science》1996,19(6):839-855
Materials are the index of human progress. The evolution of mankind is linked to materials, for example, stone age, bronze
age, iron age etc. The success of use of materials towards better quality of human life depends on the capabilities for characterization
of these materials, which leads to ensuring reliable performance of the materials and development of new, and more efficient
materials. The materials characterization encompasses determining chemical constituents, microstructural characterization
down to a few Angstroms level and defect assessment from a few micrometers to few millimeters in a wide variety of materials.
Recent progress made in the nondestructive characterization of materials and the future trends and direction are discussed
in this paper.
Text of the Presidential Address delivered at the Materials Science Section of the 82nd Indian Science Congress held at Calcutta
during January 3–8, 1995. 相似文献
17.
Xue‐Li Zheng Cao‐Thang Dinh F. Pelayo García de Arquer Bo Zhang Min Liu Oleksandr Voznyy Yi‐Ying Li Gordon Knight Sjoerd Hoogland Zheng‐Hong Lu Xi‐Wen Du Edward H. Sargent 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(23):3181-3188
TiO2 has excellent electrochemical properties but limited solar photocatalytic performance in light of its large bandgap. One important class of visible‐wavelength sensitizers of TiO2 is based on ZnFe2O4, which has shown fully a doubling in performance relative to pure TiO2. Prior efforts on this important front have relied on presynthesized nanoparticles of ZnFe2O4 adsorbed on a TiO2 support; however, these have not yet achieved the full potential of this system since they do not provide a consistently maximized area of the charge‐separating heterointerface per volume of sensitizing absorber. A novel atomic layer deposition (ALD)‐enhanced synthesis of sensitizing ZnFe2O4 leaves grown on the trunks of TiO2 trees is reported. These new materials exhibit fully a threefold enhancement in photoelectrochemical performance in water splitting compared to pristine TiO2 under visible illumination. The new materials synthesis strategy relies first on the selective growth of FeOOH nanosheets, 2D structures that shoot off from the sides of the TiO2 trees; these templates are then converted to ZnFe2O4 with the aid of a novel ALD step, a strategy that preserves morphology while adding the Zn cation to achieve enhanced optical absorption and optimize the heterointerface band alignment. 相似文献
18.
P. G. Baranov S. I. Goloshchapov G. A. Medvedkin T. Ishibashi K. Sato 《Journal of Superconductivity》2003,16(1):131-133
Electron paramagnetic (EPR) and ferromagnetic resonance (FMR) have been studied in the system of (Zn,Mn)GeP2 ferromagnetic layer grown on undoped ZnGeP2 single crystal. Strong FMR signals are registered in the wide temperature range up to room temperature. EPR and photo-EPR of intrinsic defects are observed in ZnGeP2 substrate. EPR spectra characteristic of Mn2+ ions on Zn2+ sites in the bulk appear after the growth of the ferromagnetic layer on ZnGeP2 crystal indicating the efficient Mn-diffusion into the bulk crystal by the annealing treatments. 相似文献
19.
金属氯代硫杂酞菁配位化合物敏化TiO2的研究 总被引：2，自引：0，他引：2
研究表明修饰在n-TiO_2多晶半导体电极表面上的金属氯化硫杂酞菁配位化合物,能对TiO_2产生光敏作用,在可见光区出现了光电流响应,且与该配位化合物的电子吸收光谱基本一致;敏化效果与金属氯化硫杂酞菁配位化合物的中心原子有一定的关系。 相似文献
20.
Maxwell T. Dylla Jimmy Jiahong Kuo Ian Witting Gerald Jeffrey Snyder 《Advanced Materials Interfaces》2019,6(15)
Nanostructuring to reduce thermal conductivity is among the most promising strategies for designing next‐generation, high‐performance thermoelectric materials. In practice, electrical grain boundary resistance can overwhelm the thermal conductivity reduction induced by nanostructuring, which results in worse overall performance. Since a large body of work has characterized the transport of both polycrystalline ceramics and single crystals of SrTiO3, it is an ideal material system for conducting a case study of electrical grain boundary resistance. An effective mass model is used to characterize the transport signatures of electrical grain boundary resistance and evaluate thermodynamic design principles for controlling that resistance. Treating the grain boundary as a secondary phase to the bulk crystallites explains the transport phenomena. Considering that the interface can be engineered by controlling oxygen partial pressure, temperature, and the addition of extrinsic elements into the grain boundary phase, the outlook for SrTiO3 as a nanostructured thermoelectric is promising, and the zT could be greater than 0.5 at room temperature. 相似文献