MRI: Acquisition of an Aberration Corrected High Resolution Analytical Transmission Electron Micro. for Advanced Materials Research

技术摘要：该显微镜用于确定固体中原子的空间排列及其原子分辨率的化学/键合，以进一步了解独特新材料的结构/性能关系。该显微镜工作在高达300 keV的单色场发射电子源，C3/C5球面像差校正器的探头形成透镜，高分辨率电子能量损失光谱仪，高计数率能量色散X射线光谱仪，和一个非常稳定的高倾斜范围阶段设计的断层扫描以及传统的成像。这种显微镜的当前版本已经证明了0.5 μ m的图像空间分辨率在环形暗场和亮场STEM和110 meV的能量分辨率在电子能量损失谱。用于这些模式的所有探测器都是数字的，这有利于纳米结构的定量测量和教学。这种显着的空间/能量分辨率是足够的原子/化学分布在最重要的性能确定的固体结构特征，如异相界面和晶界，催化剂表面的定量调查。此外，像差校正器使得能够使用来自枪的大电子收集角，以形成非常小且也非常高电流的电子探针，高电流探针使得能够在相对短的时间内收集许多图像和电子能量损失以及X射线光谱，以获得具有非常高分辨率的固体的二维化学图。稳定的高倾斜平台使我们能够使用层析成像将映射扩展到三维，层析成像是一种相对较新的材料科学研究成像方法，我们将彻底探索，以确定其限制。该显微镜将安装在LeRoy Eyring固态科学中心，一个多用户设施，在材料学院。外部大学和工业实验室的研究人员可以使用它进行尖端材料研究。所有材料的工程性质，如结构航空航天合金和用于计算机和手机的电子材料微芯片，取决于组成材料的原子的几何排列和化学特性。这些关系被称为？结构-性能关系？是材料科学与工程领域的重要组成部分，适用于各种材料。显微镜在材料科学和工程中的作用是确定这种关系中材料的结构。电子显微镜，特别是高分辨率分析透射电子显微镜，是我们必须确定这种关系的结构部分的最高分辨率方法。在这个项目中获得的显微镜是电子显微镜能力的最前沿，将从新的先进材料中产生许多新的和令人兴奋的结果，以提高我们国家在纳米技术中的竞争地位，它将为我们的大学生提供纳米材料表征的基本教育。这种显微镜将实现0.5毫微克（0.0000001厘米，或小于1原子直径）的图像空间分辨率，约0.001电子伏（1 meV）的纳米光谱的能量分辨率，以确定基本上在原子尺度的材料中的化学键合。这种显微镜的特殊之处在于：（1）它的电子源是场致发射型单色器;（2）显微镜中最重要的透镜的像差校正器，它消除了球面像差引起的图像模糊;（3）高分辨电子能量损失和能量色散X-射线衍射。射线光谱仪，可以确定纳米级的化学成分和键合类型，具有无与伦比的准确性。此外，该显微镜将配备一个特殊的载物台，可以改变观察样品的空间方向，使用断层扫描技术创建其化学和结构的三维地图。这些将类似于许多人熟悉的X射线CAT扫描3D图像，但在材料研究中具有更高的放大倍率和分辨率。有一个主机的重要材料的问题，将使用这种显微镜进行调查，如催化剂表面上的杂质原子如何影响其有效地生产石油基燃料的能力，以及半导体中的电活性掺杂剂原子如何可能会隔离到微芯片中的各个位置，而不是保持空间上的均匀分布。该显微镜将安装在LeRoy Eyring固态科学中心，一个多用户设施，在材料学院。外部大学和工业实验室的研究人员可以使用它进行尖端材料研究。

Technical Abstract.This microscope is designed to determine the spatial arrangements of atoms in solids and their chemistry/bonding with atomic resolution, to further understanding of the structure/properties relations of unique new materials. The microscope operates at up to 300 keV with a monochromated field emission electron source, a C3/C5 spherical aberration corrector for the probe forming lens, a high resolution electron energy loss spectrometer, a high count rate energy dispersive x-ray spectrometer, and a very stable high-tilt-range stage designed for tomography as well as conventional imaging. Current versions of this microscope have demonstrated 0.5 Å image spatial resolution in both annular dark field and bright field STEM and 110 meV energy resolution in electron energy loss spectroscopy. All detectors used for these modes are digital, which facilitates quantitative measurements of nanostructures and teaching. This remarkable spatial/energy resolution is sufficient for quantitative investigations of atom/chemical distributions at most important properties-determining structural features of solids such as heterophase interfaces and grain boundaries, and catalyst surfaces. Further, the aberration corrector enables use of large electron collection angles from the gun, to form very small and also very high current electron probes.The high current probes enable collection of many images and electron energy loss and x-ray spectra in relatively short times, to derive 2-dimensional chemical maps of solids with very high resolution. The stable high-tilt stage enables us to extend the mapping to 3-dimensions using tomography, a relatively new imaging method for materials science research that we will explore thoroughly, to determine its limits.This microscope will be installed and operated in the LeRoy Eyring Center for Solid State Science, a multiuser facility, in the School of Materials. It will be accessible for cutting edge materials research by external university and industrial laboratory researchers. Popular Publication AbstractThe engineering properties of all materials, such as structural aerospace alloys and electronic material microchips for computers and cell phones, depend on the geometric arrangements and chemical identities of the atoms that comprise the materials. These relationships are called ?structure-properties relations? and they are the major part of the field of materials science and engineering for all types of materials. The role of microscopies in materials science and engineering is to determine the structure of the materials in this relationship. Electron microscopy, in particular high resolution analytical transmission electron microscopy, is the highest resolution method that we have to determine the structures part of this relationship. The microscope to be acquired during this project is just at the cutting edge of electron microscope capability, and will produce many new and exciting results from new advanced materials to enhance our nations competitive position in nanotechnology, and it will provide essential education in nanomaterials characterization for our university students. This microscope will achieve 0.5 Ångstrom ( 0.00000001 centimeter, or less than 1 atom diameter) spatial resolution in images, and about 0.001 electron volt (1 meV) energy resolution in nanospectra, to determine chemical bonding in materials at essentially the atomic scale. The special features of this microscope that enable this spectacular performance are: (1) its electron source which is field emission type with a monochromator; (2) an aberration corrector for the most important lens in the microscope, which eliminates image blurring caused by spherical aberration; and (3) high resolution electron energy loss and energy dispersive x-ray spectrometers which can determine chemical composition and bonding type at the nanoscale with unparalleled accuracy. In addition, this microscope will be fitted with a special stage that can change the spatial orientation of the specimen under observation to create 3-dimensional maps of its chemistry and structure using tomography. These will be similar to the x-ray CAT scan 3-D images familiar to many people, but at much higher magnification and resolution for materials research. There are a host of important materials problems that will be investigated using this microscope, such as how impurity atoms on the surface of catalysts affect their ability to efficiently produce petroleum-based fuel, and the how electrically active dopant atoms in semiconductors may segregate to various locations in microchips instead of maintaining a spatially uniform distribution. This microscope will be installed and operated in the LeRoy Eyring Center for Solid State Science, a multiuser facility, in the School of Materials. It will be accessible for cutting edge materials research by external university and industrial laboratory researchers.