Poster Abstract: Transmission electron microscopes (TEMs) are an essential tool used extensively across industry and research for material science, nanoscience, and biological innovation. However, after many years of consolidation, the commercial landscape of TEMs risks becoming an oligopoly dominated by a handfulof large players; which may limit the development of new optical geometries. Much of the hesitancy for academics to propose substantial hardware modifications arises from the large purchase price, fear of voiding the warranty/service contract and the fact that many instruments sit in shared usage facilities where downtime would be unacceptable. By contrast, multiphysics simulation packages allow researchers to evaluate potential lens designs rapidly and inexpensively, without the need to disassemble the TEM column and realign it afterwards.
By simulating both the magnetic field generated by the lens and the electron path through this field, changes to the materials or geometry of the lens can be analysed. This offers a wealth of different parameters to tune for the exploration of alternative designs. With this work, we aim to outline an intuitive and accessible methodology through which electron optics can be modelled utilising a ‘virtual twin’ concept. We hope this approach encourages new, creative, and sustainable grass roots innovation to advance TEM capabilities through microscope modification. Poster
Science, education and economic development leaders across New Mexico have formed a coalition to bring future quantum computing jobs to the state.
Sandia, the University of New Mexico and Los Alamos National Laboratory announced the new coalition at UNM during the Quantum New Mexico Symposium.
Scientific Achievement: Using four-dimensional scanning transmission electron microscopy, we demonstrate a method to visualize
grains and grain boundaries in WSe2 grown by metal organic chemical vapor deposition (MOCVD) directly onto silicon dioxide. Despite the chemical purity and uniform thickness and texture of the MOCVD-grown WSe2, we observe a high density of small grains that corresponds with the overall selenium deficiency we measure through ion beam analysis. Moreover, reconstruction of grain information permits the creation of orientation maps that demonstrate the nucleation mechanism for new layers–triangular domains with the same orientation as the layer underneath induces a tensile strain increasing the lattice parameter at these sites.
Publication: Londoño-Calderon, Alejandra, Rohan Dhall, Colin Ophus, Matthew Schneider, Yongqiang Wang, Enkeleda Dervishi, Hee Seong Kang, Chul-Ho Lee, Jinkyoung Yoo, and Michael T. Pettes. “Visualizing Grain Statistics in MOCVD WSE2 through Four-Dimensional Scanning Transmission Electron Microscopy.” Nano Letters, 2022. doi.org/10.1021/acs.nanolett.1c04315
