Aberration-Corrected and In-Situ Electron Microscopy (ACAT/EM)
The Electron and X-ray Microscopy Group (EXM) at the Center for Nanoscale Materials has unique expertise with high-resolution chromatic aberration-corrected transmission electron microscopy (ACAT) and advanced in-situ TEM characterization. By integrating electron microscopy with data science approaches, these techniques provide a platform for smart and corrected imaging to reveal, with atomic resolution, the structural and chemical response in functional materials under operando conditions.
Two core capabilities are included: Smart Imaging for real-time detection and extraction of atomically resolved weak or indirect signals (local electric and magnetic fields) from a variety of detectors; and Correlated Imaging, which uses multi-beams and multi-detectors, such as X-rays, electrons and optical photons, to reveal structural and chemical response in functional materials under operando conditions.
Smart imaging leverages the unique chromatic aberration-corrected microscope ACAT and advances in data science. ACAT corrects both spherical and chromatic aberration, enabling excellent ultra-high-resolution for conventional high-resolution electron microscopy (HREM) and atomic resolution for energy-filtered HREM. It also provides a pathway for imaging of thick samples, and enables improved resolution in tomography and in-situ experiments. The chromatic aberration correction also provides enhanced contrast without sacrificing resolution, so it gives a platform for imaging of weak signals at the atomic scale. Atomic-resolution imaging of beam-sensitive nanomaterials and light element distribution in energy materials requires detection and extraction of weak signals that are typically weak due to the tendency of light elements to have weak scattering behavior. Combined with the newly-developed high speed direct electron detector, high-speed data acquisition of images and diffraction patterns under high temperatures and external electric fields is also available. This capability also provides spectroscopic characterization with energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS).
Correlated imaging combines elastic imaging by TEM at CNM for structural analysis with inelastic spectroscopy by X-rays at the Advanced Photon Source (APS) for chemical and physical probing of materials. Using the unique cross-platform in-situ sample holder with multiple external stimuli (biasing, heating, liquid/gas flow and optics), CNM is capable of correlative measurements using multi-beams and multi-detectors, such as X-rays, electrons and optical photons, to reveal structural and chemical response in functional materials under operando conditions. The complementary information from correlated imaging and spectroscopy (including EDS and EELS) provides extensive understanding of materials transformation in operando.
The CNM user program provides access to:
One of only three available worldwide, this instrument can probe thicker samples without loss of resolution and the ability to distinguish between different basis atoms in a sublattice. The FEI Titan 80-300 ST 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. For more information, contact the instrument custodian.
FEI Talos F200X TEM/STEM
This instrument is a scanning/transmission electron microscope with a X-FEG (field-emission gun), specialized in high-resolution STEM imaging. It is also equipped with a SuperX energy-dispersive spectrometer (EDS), allowing fast and precise EDS mapping. For more information, contact the instrument custodian.
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 the 200kV 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, programmable multi-point settings without mechanical drift. For more information, contact the instrument custodian.
FEI Tecnai F20ST TEM/STEM
This premier analytical transmission electron microscope (AEM) has specialized accessories that include an energy-dispersive X-ray spectrometer, a rotatable biprism for electron holography, and a post-column electron filter for both electron energy-loss spectroscopy (EELS) and energy-filtered imaging (EFI). The STEM capability enables HAADF imaging and XEDS/EELS spectrum imaging, among others. Specimen cooling and heating holders are available.
Specimen preparation is an important part of electron microscopy and an array of standard specimen preparation capabilities are available.
Building these strengths, our goal is dynamic and correlated imaging that integrates data science and detector/holder development.