Zhang X.F.,Hitachi High Technologies America Inc. |
Zhang X.F.,Hitachi High-Technologies
Springer Series in Materials Science | Year: 2014
Transmission electron microscopy (TEM) has hit a significant milestone of sub-angstrom resolution. On one hand, electron microscopists and materials scientists are enjoying the highest TEM spatial resolution ever attainable; on the other hand, study of materials in a steady state is hard to meet the increasing demand in new application fields such as nanocatalysts, nanocrystal growth, nanoelectron-ics, nanosensors, and nanomechanics in which size effect and structural or property responses to stimuli from the surrounding environment are key information to learn. Special attention is thus paid to in-situ TEM. A great deal of effort in developing and improving electron microscopes and specimen holders have resulted in unprecedented progresses in attaining insight into materials in dynamic environments. In many ways, transmission electron microscopes are now functionalized as workstations or nanoscale labs rather than just imaging tools. In this chapter, various types of in-situ TEM technologies are introduced accompanied by application examples. In parallel to the sub-angstrom breakthrough made by the aberration-corrected TEM, atomic resolution is now emphasized in advanced in-situ TEM, advancement on this aspect will be discussed together with other important notes and further challenges. © Springer-Verlag Berlin Heidelberg 2014. Source
Teshima J.,LatticeGear LLC |
Clarke J.J.,Hitachi High Technologies America Inc.
Solid State Technology | Year: 2014
Experts demonstrate preparation of SEM cross-sections by combining site-specific high-accuracy cleaving (HAC) and broad ion beam (BIB) milling. The experts demonstrate that combining these cost-effective milling techniques reduces sample preparation time, complexity, and cost without compromising cross-section quality. The LatticeAxTM HAC and Hitachi IM4000 BIB milling tools have been used to demonstrate this process. The LatticeAxTM overcomes the disadvantages of other conventional milling techniques by controlling the indent location and depth, along with the cleaving operation, with fine-positioning on the LatticeAxTM high magnification digital microscope. Source
Gordon R.,Hitachi High Technologies America Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013
In this presentation, Hitachi High Technologies America (HTA) introduces its Educational Outreach Program and explains it's involvement with Change The Equation (CTEq), a nonprofit, nonpartisan, CEO-led initiative that is mobilizing the business community to improve the quality of science, technology, engineering and mathematics (STEM) learning in the United States. © 2013 SPIE. Source
Suzuki M.,Hitachi High-Technologies |
Yaguchi T.,Hitachi High-Technologies |
Zhang X.F.,Hitachi High Technologies America Inc.
Journal of Electron Microscopy | Year: 2013
Quantitative modeling for high-resolution (phase contrast) gas cell environmental transmission electron microscopy (ETEM) imaging is presented in this paper. Concepts of pre-specimen scattering object (PreSO) and post-specimen scattering object (PoSO) are introduced to explain electron scattering caused by gas and window membranes associated with the gas environmental cell (E-cell). PreSO preserves the structural phase information and the effect can be evaluated by averaging the contrast transfer functions (CTFs) over random electron scattering. PoSO is treated as information loss and the unscattered electrons play a major role in determining the ETEM image quality. The theoretical model is compared and matched well with our systematic gas ETEM experimental results under various gas pressures. Extension of our approach to the aberration-corrected ETEM is discussed. © The Author 2013. Published by Oxford University Press [on behalf of The Japanese Society of Microscopy]. All rights reserved. Source
Zhu C.,Washington University in St. Louis |
Zhu C.,Nanjing Southeast University |
Zhu C.,Georgia Institute of Technology |
Zeng J.,Washington University in St. Louis |
And 8 more authors.
Journal of the American Chemical Society | Year: 2012
This article describes a systematic study of the nucleation and growth of Ag (and Au) on Pd nanocrystal seeds. By carefully controlling the reaction kinetics, the newly formed Ag atoms could be directed to selectively nucleate and then epitaxially grow on a specific number (ranging from one to six) of the six faces on a cubic Pd seed, leading to the formation of bimetallic nanocrystals with a variety of different structures. In addition to changing the injection rate of precursor, we also systematically investigated other reaction parameters including the capping agent, reductant, and reaction temperature. Our results suggest that the site-selective growth of Ag on cubic Pd seeds could be readily realized by optimizing these reaction parameters. On the basis of the positions of Pd seeds inside the bimetallic nanocrystals as revealed by TEM imaging and elemental mapping, we could identify the exact growth pathways and achieve a clear and thorough understanding of the mechanisms. We have successfully applied the same strategy based on kinetic control to cubic Pd seeds with different sizes and octahedral Pd seeds of one size to generate an array of novel bimetallic nanocrystals with well-controlled structures. With cubic Pd seeds as an example, we have also extended this strategy to the Pd-Au system. We believe this work will provide a promising route to the fabrication of bimetallic nanocrystals with novel structures and properties for applications in plasmonics, catalysis, and other areas. © 2012 American Chemical Society. Source