Jon Poplawsky, a materials scientist at the Department of Energy’s Oak Ridge National Laboratory, develops and links advanced characterization techniques that improve our ability to see and understand atomic-scale features of diverse materials for energy and information technologies.
His forte is atom probe tomography (APT), a method that can identify the three-dimensional (3D) positions and species of atoms within a volume of material with sub-nanometer resolution. The atom probe pulls atoms off the tip of a needle-shaped sample, atom by atom. When the experiment is done, the material is consumed. The identity of each atom is determined from time-of-flight mass spectrometry as the atom travels from the tip of the needle to the detector for mapping. While APT cannot always extract atom-level structural information, it gives a general 3D picture of the distribution and identities of individual atoms.
“The atom probe is like a movie that you can freeze to see one frame at a time,” Poplawsky explained. “You can see each atom reconstructed in 3D and understand what happened to the atoms because of a given process.”
Poplawsky has used this precise, accurate instrument to characterize zeolite catalysts, solar cells, light-emitting diodes, structural materials, battery materials, semiconductor devices, ceramics and other diverse materials.
Department of Energy
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Oak Ridge, TN 37830
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