Low dimensional materials had, and continue to have, a huge potential to revolutionize the development of technological devices. For low dimensional materials, which often consist of just a single layer of atoms, it is essential to be able to examine their atomic structure and develop an understanding of how it influences the device properties. Transmission electron microscopy (TEM) is one of the only means by which atomic structures of low dimensional materials can be studied. Until recently, the spatial resolution of TEMs was inherently limited by the aberrations of the optical imaging system. However, the development of aberration correctors, the equivalent of a pair of reading glasses, which correct for some of the microscope's aberrations (e.g. astigmatism), has allowed improvement of spatial resolution of atomic-scale images by more than a factor of three. In 2010, as part of the ARRA-funded NSF-MRI-R2 program, the University of Illinois at Chicago was awarded a grant to acquire an aberration-corrected scanning transmission electron microscope (STEM), which can achieve single atom resolution on a routine basis. This current project will upgrade one of the most crucial components of the this instrument: the electron energy-loss spectrometer (EELS). The upgrade will impact the research of the more than 150 users, including the 13 co-PIs and collaborators at the University of Illinois at Chicago (UIC), surrounding institutions and from around the world. The installation of this upgraded EELS system dramatically improves the teaching and outreach capabilities of the involved faculty at UIC, and establishes a regional center of excellence in a central Midwest location providing unparalleled TEM instrumentation access to students and scientist
Transmission electron microscopy (TEM) is an essential tool in the study of the atomic-scale structure-property relationships of functional nano-materials and 2-dimensional materials systems. With the development of aberration correctors and cold-field emission electron sources, the spatial resolution of TEMs operated at 200kV has now reached 70 pm with an energy resolution of better than 350 meV. This project seeks funding to upgrade the existing electron energy-loss (EEL) spectrometer on the aberration-corrected cold field-emission JEOL ARM200CF STEM/TEM to better serve the materials science research and education at the University of Illinois - Chicago (UIC). The proposed upgrade will replace the current Gatan Enfina spectrometer with a Gatan Dual EELS Quantum spectrum-imaging filter, an advanced, high-speed, high-sensitivity spectrometer with increased energy resolution. In doing so, the PIs will dramatically improve i) the attainable spatial resolution during EEL spectrum imaging due to the presence of a camera at the end of the imaging filter; ii) the acquisition speed of individual EEL spectra or entire spectrum images due to the acquisition electronics and increased collection efficiency; and iii) the energy resolution and range due to higher-stability electronics and more efficient acquisition cameras. The broader impacts on the TEM community in the Midwest and the local educational resources will be significant. The upgraded instrument will continue to be operated by UIC's Research Resources Center, a center of excellence for teaching and training of advanced TEM. The faculty at UIC will further use the instrument to develop strong collaborative interactions with groups at surrounding academic institutions and industrial laboratories, as well as collaborators from around the world to maximizing the outreach opportunities for training and research of UIC's diverse student body.
