MRI: Acquisition of a State-of-the-Art Aberration-Corrected Analytical Electron Microscope with Enhanced Atomic-Level Spectrometry and Low-Voltage Performance

Lehigh University, Bethlehem PA

Investigators

Abstract

Technical Summary: Researchers at Lehigh University have acquired a JEM-ARM200F aberration corrected analytical electron microscope (ACAEM), which is equipped with a cold field emission gun and can be operated at low accelerating voltages. This instrument has excellent column stability, improved electronic stability, extremely low sample drift and incorporates the latest generation of aberration corrector. The microscope will also be equipped with a Gatan Quantum energy filter and a high area silicon drift detector (SDD) to routinely allow chemical analysis by electron energy-loss spectrometry (EELS) and X-ray energy dispersive spectrometry (XEDS) at atomic resolution. The instrument will offer new insights into interfacial phenomena such as grain boundary segregation in metals; interfacial complexions in ceramics; domain boundaries in ferroelectrics; inclusions and ferroelectric architecture in glass; and the epitaxy of semiconductors on patterned substrates. In the realm of nanomaterials, the instrument will facilitate the development of new catalysts for fine chemical production, pollutant removal, and upgrading the octane rating of gasoline. In addition, novel types of nanoporous materials will be studied that have applications spanning the production of bio-fuels and renewable chemicals, to CO2 capture and dialysis separations. The JEM-ARM200F will also give researchers the capacity to analyze soft and ultra-beam sensitive materials (e.g. polymers, zeolites, compounds containing lithium, carbon nanotubes wrapped with DNA) that are quickly destroyed in conventional transmission electron microscopes. The proposed instrument will be housed within the electron microscopy user facility at Lehigh University which is world-renowned for its electron microscopy research, education, and training. Layman Summary: Just as the Hubble space telescope was discovering giant galaxies at the edge of the universe, a quiet revolution in electron microscopy was taking place that offered a much improved view of the nanoworld. The ability to correct the aberrations, or distortions, that exist in electron lenses has enabled scientists to collect images with a resolution that could never have been achieved with conventional electron microscopes. Lehigh was the first university in the world to acquire two aberration corrected microscopes: one primarily dedicated to atomic resolution imaging, and the other optimized for chemical analysis. Both instruments have been fully utilized for the characterization of metals, catalysts, ceramics and semiconductors; the results of these studies have appeared in many high profile journals (e.g. in Nature and Science). Despite this improved capability, performing chemical analysis with atomic resolution is still a struggle. In addition, the current Lehigh microscopes only work at accelerating voltages of 200 and 300kV which is not suitable for the study of beam sensitive materials such as those containing lithium, glass, polymer, or biological matter. Both of these obstacles are overcome with the purchase of the latest JEM-ARM200F aberration corrected analytical electron microscope equipped with a field emission gun that can be operated at lower accelerating voltages, and state-of-the-art electron energy loss and X-ray energy dispersive spectrometers enabling chemical analysis with atomic resolution to be performed on a routine basis. Lehigh's electron microscopy laboratory acts as key multi-user facility and a center for electron microscopy education and training. Through its world-renowned microscopy schools, Lehigh serves thousands of research scientists and engineers from academia and industry as well as many government laboratories, all of whom will benefit from having access to state-of-the-art equipment.