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 Ã… 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 Abstract The 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 Ã…ngstrom ( 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.
