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.
In this project, we acquired a state-of-the-art JEM-ARM200CF, which has markedly better performance characteristics in that it can be (i) operated at much lower accelerating voltages, and (ii) is stable enough to routinely perform atomic resolution chemical analysis. This advance allows us tackle a wide range of materials problems that are important to the current research portfolios and future research aspirations of our faculty. The new instrument JEM-ARM200CF has been installed at Lehigh and initial performance tests have been completed. Intellectural merit activities Based on the funding through this NSF MRI program, we have been seeking a new state-of-the-art aberration-corrected analytical electron microscope for (i) improved atomic-level analysis and (ii) enhanced low-voltage performance at Lehigh. Both the features in the new instrument are absolutely essential to characerize advanced materials. To achieve both the features, the PIs visited to JEOL factory, Tokyo Japan, several times to finalize instrument configurations and to gather some test data by using a prototype instrument. By evaluating data obtained from the prototype instrument, the configurations of new instrument was finalized. Then, the JEM-ARM-200CF instrument was installed at Lehigh. Prior to the installation, we have modified the room to reduce all possible sources for noise and interference. The installatin was completed and signed-off in the end of November 2012 (supporting image 1). It was confirmed that image resolutions in the STEM mode reach to 78 pm at 200 kV and 136 pm at 60 kV (supporting image 2). In addition, atomic-resolution X-ray maps ahve successfully been acquired (supporting image 3). Since then, the instrument has been available for users, mainly graduate students and post-doctral fellows from various departments at Lehigh, e.g. Materials Science & Engineering, Chemical Engineering, Chemistry, Physics, etc. Since the installation, the instrument was used over 170 session (for the usage, only one session is counted a day), excluding training sessions and instrument down time for services. Over 10 sessions were used by female students/post-docs. This instrument has been applied to many research projects in the areas of (i) interfacial science, (ii) nanomaterials, (iii) glasses and (iv) soft materials. By using the new instrument, for example, specific locations of impurity elements could be identified along a grain boundary in Cu (supporting image 4) and nanocomposite polymers could be observed without damaging at 60 kV (supporting image 5). Broader Impact activities The concepts developed within this research grant for acquisition of the new state-of-the-art JEM-ARM200CF instrument and results ontained by using the instrument have been (or will be) disseminated at varirous conferences and seminars at other Universities and research institutions from 2010 to 2013. In doing so, the discipline of materials science and engineering, and the sub-discipline of analytical electron microscopy in particular, has been impacted in a significant way. Over 100 invited talks on the new instrument have been given by the PIs during this funding period. In addition, after the installation, many users have been using this instrument for their research. Results obtained using the JEM-ARM200CF instrument were presented in various conferences and workshops by graduate students. Within one year of operation, over 15 conference talks were presented by graduate students. Furthermore, the instrument was used for demonstration of high resolution imaging both in the TEM and STEM modes in MAT423 Advanced TEM class for 10 graduate students in 2013 spring semester. This instrument was also used for demonstrations in Lehigh Microscopy School in June 2013.
