MRI: Acquisition of an Analytical Transmission Electron Microscope for High-resolution, Rapid Nanoscale Compositional Mapping of Earth, Planetary, and Advanced Materials

University Of Arizona, Tucson AZ

Investigators

Abstract

This award from the Major Research Instrumentation program and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate supports the acquisition of a high-resolution, analytical transmission electron microscope (TEM) by the University of Arizona (UA). The TEM suppports scientists in characterizing nanoscale compositional and structural properties of natural and advanced materials of significance for multiple federally funded research projects. These range from planetary materials providing insight into the origins of our solar system and planet, to nanomaterials broadly impacting the next generation of electronic, optical, and energy-harvesting technologies central to the national interest. This regionally unique research instrument is a showcase for modern measurement science in the US Southwest region and serves universities with diverse and underserved student populations. The TEM acquisition is accompanied at UA by: (a) the development of a new undergraduate course in electron microscopy; (b) annual electron microscopy workshops to expand the regional user base; and (c) a symposium series to stimulate cross-disciplinary interactions between all users of this instrument. The research, training, technology development, education and outreach efforts enabled by this facility serve as a focal point for forming robust partnerships and mentoring relationships that promote recruitment and retention in STEM fields and training the next generation of highly skilled scientists to support growth of the high-tech sector in the US economy. The high-resolution, analytical transmission electron microscope (TEM) at the University of Arizona (UA) is specifically configured to provide rapid, atomic-scale chemical and structural information on a wide range of materials. The instrument acquires elemental maps in minutes at nanometer length scales. Enhancements that dramatically improve X-ray counting statistics lead to: (a) enhanced elemental mapping; (b) negligible drift artifacts in scanning TEM and energy-dispersive X-ray spectroscopy/electron energy-loss spectroscopy; and (c) improved spatial coherence for high-resolution imaging. The diverse research programs impacted by the new instrument include the characterization of: presolar stardust grains and circumstellar materials; catalyst-tipped semiconductor nanorods for solar-driven fuel formation; electrical contacts and perovskite active layers in photovoltaics; grain boundaries in metallic ceramics; nanopillar magnetic tunnel junctions; oxygen-conducting electrolytes; solar water splitting materials; high-pressure terrestrial materials; 3D-printing materials; quantum dots as new electronic materials; and photonic materials. Each of these activities has been limited by the lack of routine access to instrumentation that combines rapid mapping of elemental composition on nanometer length scales with TEM imaging. This state-of-the-art instrument establishes the essential feedback loop between characterization and materials research, and enables cross-disciplinary science and student training.