The NUCAPT research facility at Northwestern University specializes in three-dimensional high-resolution analytical imaging and materials analysis by atom-probe tomography (APT). With sub-nanometer resolution in 3-D and high analytical sensitivity for all elements in the periodic table, APT is particularly suited to study nano- and nanostructured materials from research fields such as nanotechnology, materials science and related engineering sciences, semiconductor materials and electronic devices, energy materials, and samples from chemistry, life sciences (biomaterials), and geo- and planetary sciences. NUCAPT operates a CAMECA LEAP 5000 XS atom probe tomograph with 80% atomic detection efficiency.
NUCAPT's LEAP 5000 XS
NUCAPT operates a CAMECA LEAP5000 XS tomograph, featuring 80% detection efficiency, straight flight path, ultra-violet (355 nm wavelength) laser pulsing with pulse rates up to 1 MHz, voltage pulsing, local-electrode design, wide-angle field-of-view, and microtip array capability. Specimen datasets of 1-5x108 atoms are recorded routinely, corresponding to a specimen volume of approximately 0.15 x 0.15 x 0.5 μm3.
Research Examples
Nano-scale precipitates in a HEA alloy
Cuboidal precipitates enriched in Ta, Nb, and Mo in a matrix rich in Al, Ti, and Zr, in an AlMo0.50NbTa0.50TiZr bcc high-entropy alloy. An 18 at.% Ta isoconcentration surface is superposed in red to outline the two-phase microstructure. “Development of a Refractory High Entropy Superalloy,” O. N. Senkov, D. Isheim, D. N. Seidman, A. L. Pilchak, Entropy 18, 102, 2016.
InAs/GaSb superlattice
“Atomic intermixing in short-period InAs/GaSb superlattices,” Y. Ashuach, Y. Kauffmann, D. Isheim, Y. Amouyal, D. N. Seidman, E. Zolotoyabko, Applied Physics Letters Vol. 100 (24) 241604.
Meteoritic Nanodiamonds
”Atom-Probe Analysis of Nanodiamonds from Allende,” P.R. Heck, F.J. Stadermann, D. Isheim, O.H. Auciello, T.L. Daulton, A.M. Davis, J.W. Elam, C. Floss, J. Hiller, D.J. Larson, J.B. Lewis, A. Mane, M.J. Pellin, M.R. Savina, D.N. Seidman, T. Stephan, , Meteoritics & Planetary Science, 49, 453–467 (2014).