From Northwestern University Center for Atom-Probe Tomography
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The main chamber of the 3DAP

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NUCAPT specializes in high-resolution chemical imaging by three-dimensional atom-probe tomography (APT). APT produces a three-dimensional (3-D) image of a sample volume, resolved atom-by-atom, elementally and isotopically, and with sub-nanometer spatial resolution A typical APT run typically captures a volume 100 x 100 x 300 nm^3 of a sample by field-evaporating atoms from the specimen surface in a high electric field, atom-by-atom, atomic layer by atomic layer. A high resolution direct-space image is recorded at about one million time magnification, and the chemical and isotopic identity of each atoms determined simultanously by time of flight mass spectrometry. With sub-nanometer spatial resolution and elemental and isotopic sensitivity for all elements across the periodic table, APT is particularly suited to study nano- or nanostructured materials.

Typical micro- and nanostructural features studied at our research facility include: composition and morphology of second-phase precipitates, segregation and small clusters of solute atoms at grain boundaries and phase boundaries, compositional variations in modulated structures, multi-layer thin-film structures, dopant profiles in semiconductor materials and devices, and analysis of the chemistry and topology of internal (buried) interfaces. Typical materials studied include high-performance metallic alloys (steels, Al-, Mg-, Ni-, Ti-, Co-, Mo-, Nb- and shape memory alloys), semiconductor nanowires and devices, zero-, one, and two-dimensional quantum well structures, thin-film functional materials, nanoparticle growth morphologies and nanomaterials for catalysis and environmental remediation, nanodiamond particles, tooth enamel, bones, biominerals, and hybrid materials, geological materials including meteoritic, lunar, and geological materials, battery and energy materials, including electrode materials for Li-ion batteries and fuel cell barrier layers, and materials from cultural heritage and art such as glass, ceramics and paint pigment.

Specimen preparation of almost any material is now possible employing a dual-beam focused-ion beam (FIB) microscope, which also allows targeted sample preparation of a specific feature, such as a grain boundary or an individual transistor in a semiconductor device.

Instruments: LEAP, IBS/e

Specimen Preparation: electropolishing, FIB

Computing Computers, Apex, IVAS, LibX, Mailing Lists, Remote Access,



Instruments operated previously: FIM, 1DAP, PLAP

Feedback Imago Feedback, Apex Feedback, Tip Electropolishing


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Pages in category "Tools"

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