This Major Research Instrumentation award supports North Carolina State University (NCSU) with the acquisition of a high-resolution scanning electron microscope that can produce electron beams with landing energies lower than 0.1 keV while retaining lateral resolution below 1 nm. The proposed instrument enables imaging with beam currents below 5 pA. This combination of low landing energy and low current brings three transformational capabilities to NCSU: 1) it is possible to eliminate surface charging by balancing energy dependent electron arrival and emission rates; 2) it is possible to acquire information that is highly surface specific; and 3) it is possible to minimize beam damage in materials that would otherwise deteriorate rapidly. In combination, these capabilities will propel existing research by providing structural information at dramatically higher resolution and on samples that simply could not be imaged previously. These capabilities will enhance materials research at NCSU that is increasingly interdisciplinary, with focused efforts on electronic heterostructures, nanofiber/nanoparticle composites, colloidal assemblies, and DNA-mediated organic-inorganic assemblies. *****
This Major Research Instrumentation award supports North Carolina State University (NCSU) with the acquisition of an extreme-resolution scanning electron microscope that images with low energy electrons. The key benefit of this instrument is imaging with a resolving power approaching atomic dimensions without the limitations due to the accumulation of negative charges on the sample surface that severely limits image quality and resolution. Furthermore, this low energy probe allows researchers to explore organic substances like plastics, natural fibers, and in some cases cells, which would decompose rapidly if imaged in a conventional instrument. This instrument will strengthen existing interdisciplinary programs at NCSU and is the greater Research Triangle region through its ability to characterize a diverse palette of materials at extreme resolution. In addition the instrument will create new outreach opportunities to inspire future generations of students in science, technology and math disciplines.
Technical Merit NCSU receive funding to aquire a low-voltage extreme resolution scanning electron microscope that can image beam sensitive and insulating materials with sub nanometer resolution. These abilities result from a new beam decelleration technology that allows one to eliminate (in almost all cases) sample charging with minimal sacrifice of lateral resolution. Beam deceleration also provides for extremely shallow electron interaction volumes, which provides extreme sensitivity to surface topography. The microscope can image samples with electron landing energies between 50 and 30,000 volts. This broad range enables one an extremely broad spectrum of imaging conditions, and thus a similarly broad set of sample types. In addition to the extremely sensitive electron source, the microscope features 5 different detectors, each of which can sample signal electrons with unique characteristics. Collecting and comparing images from different detectors further enables one to expand the investigative power. Broader Impact This new instrumentation enables NCSU and the regional research community to image samples at resolutions that were previously impossible. The set of samples that can be examined are now expanded to those which are electrically insulating, comprised of polymeric precursors, and in some cases those from biological origins. Numerous users from NCSU, international companies, and international universities have open access to the instrument. The new microscope has been impactful for outreach events at NCSU. It's ability to image nanostructures has made it an important component of events including: NCSU NanoDays, Materials Camp, and STEM Play Corps.
