This Major Research Instrumentation (MRI) award supports the acquisition of a high-resolution low-voltage electron microscope at the University of Georgia (UGA) that enables the research, training, teaching, and outreach efforts of investigators across the physical sciences, geological and environmental sciences, biological sciences, engineering disciplines, and allied fields. The unique technical capabilities of this microscope allow the imaging and chemical analysis of samples under conditions that mitigate electron beam damage. These capabilities lead to the study of diverse materials including nanostructures, polymers, fibers, and biological specimens, which encompass research being done by 29 major users across numerous colleges, centers, departments, and laboratories at UGA. This instrument is integrated within the Georgia Electron Microscopy (GEM) core facility at UGA to permit inter- and transdisciplinary usage and collaboration. Beyond research applications and the associated training of student users, the new microscope enables the inclusion of state-of-the-art electron microscopy content in course offerings and outreach efforts. These activities are accomplished in part using GEM's Electron Theater, with an emphasis on nanoscience in the environment. In addition, the instrument is used to acquire data sets suitable for integration into K-12 STEM lesson plans.
This MRI award supports the acquisition of an electron microscope capable of low-voltage operation (defined as less than or equal to 30 kV). The technical highlights of this instrument include ultra high-resolution scanning electron microscopy (UHR-SEM) imaging at low voltages; high resolution scanning transmission electron microscopy (STEM) mode, including high-angle annular dark field (HAADF) imaging and additional detectors, all operating at a low beam voltage; and analytical tools that provide quantitative composition and structure data, including electron diffraction, elemental mapping by energy dispersive X-ray spectroscopy (EDS), and electron energy-loss spectroscopy (EELS), all at low voltages. Research projects enabled by this instrument span four thematic areas: (1) inorganic nanomaterials, especially 2D nanosheets and functional materials for energy storage, electronics applications, biomedical imaging, and drug delivery applications, (2) nanogeoscience and environmental soil science, (3) new frontiers in developing high-resolution low-voltage methods for imaging biological specimens, and (4) high-resolution low-voltage imaging of nanostructured hybrid systems and soft materials, including beam-sensitive samples like polymers and fibers. In particular, the application of electron microscopy to beam-sensitive materials will provide new detailed information about sample composition, heterogeneity, structure, phase purity, and properties at the nanoscale. Additionally, the superior contrast in STEM brightfield and HAADF imaging modes, compared with TEM imaging, will allow investigators to resolve detailed organic components, such as the ligand coronas of inorganic nanostructures and interfaces between biological structures.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
