Acquisition of a STEM Cs Corrector for sub-A Resolution Imaging and Spectroscopy

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

An award is made to the University of Illinois at Chicago (UIC) to purchase an aberration corrector. The instrument will be installed on an existing scanning transmission electron microscope (STEM) at the UIC. The increasing use of multi-component semiconductors, oxides and composite systems to exploit exotic electronic and chemical properties, makes it crucial to understand the precise role an interface or defect plays in controlling a particular device function. A fundamental new pathway to a basic atomistic understanding of interface and defect properties has recently been developed in the STEM. Scanning a highly stable probe of atomic dimensions can generate an incoherent, atomic resolution Z-contrast structural image. As the high-angle detector used to form this image does not interfere with the analytical peripherals, the image can be utilized to position the electron probe for simultaneous spectroscopic analysis on the atomic scale. The resolution of these comprehensive STEM techniques is only limited by the ability of the microscope to form a small electron probe; a limitation that is imposed by the spherical aberration of the probe-forming lens. The aberration corrector will help overcome this limitation, improving the resolution to below 1. This will open up a much wider range of key materials systems, defects and interface structures that can be routinely analyzed. This new capability will be used to investigate grain boundaries in electronic oxides, hetero-interfaces in semiconductors, quantum dots, carbon nanostructures and heterogeneous catalysts. This IMR award is for the acquisition of an aberration corrector by the University of Illinois at Chicago (UIC). The new instrument will be installed into a dedicated scanning transmission electron microscope. Such a corrector will allow unprecedented spatial resolution (sub nanometer) in the analysis of materials interfaces and defects and will support vigorous research programs in such diverse technological areas as superconductors, semiconductors, ceramic oxides and catalysts. The PI, co-PIs and users of the instrumentation span a wide range of the pure and applied physical sciences and include collaborators from both local and national research institutions. This instrumentation will be an integral component of an established facility in the UIC Research Resources Center, specializing in atomic scale studies of materials. The expertise of the staff in the facility and the stability of the laboratory creates a unique opportunity for achieving the desired performance. As with other instruments in the UIC facility, this microscope and the support staff will also be made fully available to other researchers. The new microscope will also strengthen established outreach activities, promoting the benefits, achievements and excitement of research to high school teachers, students and parents as well as providing valuable experience to graduate and senior level undergraduate students.