Electron Microscopy

Ultrafast Electron Microscopy (UEM)

Our UEM combines (a) a tunable femtosecond laser with a high repetition rate, (b) multiple routes to produce a pulsed electron beam, and (c) a synchronous laser-pumped, pulsed transmission electron microscope that is outfitted with high-sensitivity cameras and electron energy filtering. The UEM can work in different modes of imaging, diffraction, and spectroscopy.  This tool opens the door to the understanding of fast (sub-picosecond to nanosecond) dynamics and short-lived metastable phases in materials with sub-nanometer spatial resolution. 

Spectra 200 STEM

This Thermo Fisher Spectra 200 scanning/transmission electron microscope (S/TEM) is under installation and expected to open to users in the first quarter in 2023. It has a cold-field emission gun (C-FEG with 0.3 eV energy resolution), a Cs probe corrector for sub-0.1 nm resolution HAADF imaging; a Super X energy-dispersive spectrometer (EDS) for atomic resolution EDS mapping, Gatan energy-filter imaging and electron energy loss spectroscopy (EELS); a bi-prism; and an EMPAD for 4D-STEM.

Aberration-Corrected TEM

Argonne Chromatic Aberration-corrected TEM (ACAT) is a FEI Titan 80-300 ST that has a CEOS Cc/Cs corrector on the imaging side of the column to correct both spherical and chromatic aberrations. The Cc/Cs corrector also provides greatly-improved resolution and signal for energy filtered imaging and EELS. Low-dose HREM imaging is available using the direct electron detection camera.

JEOL JEM2100F TEM

The JEM-2100F is an advanced field emission electron microscope featuring ultrahigh resolution and rapid data acquisition with the highest image quality and the highest analytical performance in 200-kV class analytical TEM with a probe size under 0.5 nm. A side-entry goniometer stage provides easy use of tilt, rotation, heating and cooling, and programmable multi-point settings without mechanical drift. It is equipped with a Gatan Imaging Filter system and can be operated in Lorentz mode at low magnification.

FEI Talos F200X TEM/STEM 

This instrument is a scanning/transmission electron microscope with an X-FEG field-emission gun and specializing in high-resolution STEM imaging. It is equipped with a Super X energy-dispersive spectrometer (EDS) allowing for fast and precise EDS mapping. 

Zeiss NVision 40 FIB-SEM

This platform accommodates site-specific TEM sample preparation, 3D data acquisition, nanofabrication and manipulation, and other advanced uses. Simultaneous electron and ion scanning offers unique imaging and fabrication opportunities.

Other Instruments

• Hitachi S-4700-II — high-resolution, high-vacuum SEM
• FEIQuanta 400F— high-resolution environmental and variable-pressure SEM
• JEOL IT800HL — high-resolution, hybrid lens SEM

Support Facilities

Specimen preparation is an important part of electron microscopy and an array of standard specimen preparation capabilities are available. While users are expected to carry out their own specimen preparation, expertise and guidance may be provided by CNM staff.

Theory

Would you like Theory with that? Joint experimental-theory proposals are possible and encouraged; visit the Theory & Modeling group’s webpage for more information about their capabilities.

X-Ray Microscopy

Hard X-ray Nanoprobe (HXN)

The CNM/APS Hard X-ray Nanoprobe (HXN) facility at beamline 26-ID of the Advanced Photon Source (APS) delivers a hard X-ray beam tunable over the 8-12 keV spectral range and focused to 25 nm onto the sample. This X-ray energy range is ideal for probing crystalline thin films, devices and interfaces, and many inner-shell electronic resonances and for mapping most elements in the periodic table. The HXN uses interferometric control to maintain relative positional drift of the focusing optics and sample less than 10 nm/h. The working distance between the X-ray focusing optics and the sample is typically a few mm, enabling a variety of in-situ and operando experiments with variable temperature, applied electric and magnetic fields, and  liquid and gaseous environments. A heating/cooling specimen stage supports variable temperature experiments with the HXN over a temperature range of 100-525 K with a step-size of 0.01 K and stability of 0.005 K.

Scanning Nanodiffraction and Bragg Ptychography

Nanoscale structural information, such as crystallographic phase, strain, and texture, are measured at the HXN at a spatial resolution down to 30 nm by recording how a crystalline sample diffracts the incident nanofocused X-ray beam while on the Bragg condition as the focus is scanned over the sample. Bragg ptychography, a scanning coherent diffractive imaging technique that exploits the coherence of the nanofocused X-ray beam combined with iterative phase retrieval methods, provides nanoscale structure and lattice strain information within crystalline samples at a resolution that has been demonstrated to 5 nm, well beyond that of current hard X-ray focusing optics. Scanning nanodiffraction and Bragg ptychography are in high demand at the HXN as tools for probing crystal ordering, defects, and phase transitions in nanomaterials.

Multimodal Chemical and Structural Nanoimaging

The CNM/APS HXN is uniquely capable of chemical and structural nanoimaging at a resolution of ~30 nm by exploiting its scanning fluorescence X-ray microscopy (SFXM) capabilities. In SFXM, the spatial distributions of the elements in a sample are mapped by scanning a nanofocused X-ray spot over it as the emitted fluorescence X-rays are measured by an energy-dispersive detector. Characteristic fluorescence X-rays emitted by the sample uniquely identify the elements present in it with 1000 times greater sensitivity than electron probes; the incident photon energy can also be tuned over absorption edges to analyze the sample’s chemical state. Nanoscale elemental and chemical mapping with the HXN enables understanding material properties, such as trace contaminants, second-phase particles, defects, and interfacial segregation.  This approach can be used to image samples under various in-situ/operando conditions, and is particular well suited to 3D study of highly complex, heterogeneous, and non-crystalline nanomaterials.