STEM

The FEI 200kV Titan Themis STEM is a scanning transmission electron microscope with several key capabilities.

FEI 200kV Titan Themis STEM

Independent Usage

If you are a certified operator of the FEI Titan Themis STEM, please fill out the ACMAL/STEM - Titan Themis - Independent Usage form before using the instrument. Include intended techniques, and sample identification and date reserved at the instrument. Make reservations as usual and then submit the form.

Independent Usage Request

Overview

Michigan Tech recently commissioned a FEI 200kV Titan Themis Scanning Transmission Electron Microscope (STEM). This microscope positions Michigan Tech faculty on the leading edge of new imaging capability for structural and chemical analysis at the nanoscale. The microscope is housed in a building specially constructed for such an instrument capable of atomic resolution. This instrument represents one of only two Titans found in higher education in the state of Michigan. The Themis has a full complement of state-of-the-art accessories, including specialized specimen holders that extend the STEM utility.

TEM Grids

Pure Metal Grids

  • Cu-grids, 300 mesh and 400 mesh (square mesh) (at M&M 631)
  • Cu-Omniprobe Cu Lif-out-grids (3 posts) (at the FIB lab)
  • Cu-Folding grids hexagonal mesh (at M&M 631)

TEM Grids with Support Film

All Carbon Type-A at M&M 631.

  • Cu-grids with a continuous C-film (Cu-CF)
  • Cu-grids with a Formvar stabilized lacey C-film (Cu-FLC)
  • Cu-grids with a ultra-thin coated lacey C-film (Cu-UTLC)
  • Cu-grids with a lacey C-film  (Cu-LC)
  • Ni-grids with a lacey C-film  (Ni-LC)
  • Ni-grids with a ultra-thin coated lacey C-film  (Ni-UTLC)

Special Grids

Contact Erico Freitas to obtain grids.

  • Au-grids with a ultra-thin coated lacey C-film 
  • Cu-grids with a silicon monoxide film
  • Cu-single slot coated with a Formvar film
  • Silicon frames with a square well coated with SiN film 
  • Cu-grids with single layer graphene coated lacey C-film

See the PELCO® TEM Grid Support Film Application Guide from Ted Pella, Inc., for a useful chart to help you find out what type of TEM grid works best for your TEM work. Most of the listed types of substrates in that table are available for the ACMAL STEM users.

Grid Instructions

  1. Slide off the lid of the desiccator to open it. It is fragile, so be careful.
  2. Use the provided pair of tweezers (inside the desiccator) to pick up the grids you need. Handle tweezers with care. Their tip can easily bend and get damaged.
  3. Always manipulate the grids over a clean surface (piece of Al foil or kimwipe).
  4. Take the type and number of TEM grids you need.
  5. Fill in the log book.
    1. Date
    2. User name
    3. Grid box ID
    4. # grids taken
    5. Grid positions
    6. Observations
  6. Write down your name in the original grid position in the grid box map. (See in the piece  of paper inside the bag—follow the legend when filling in the provided grid box map.)
  7. Place the tweezers back in the desiccator.

A view of the S-TEM set up.

Watch Under the Titan Lens: Microscope Takes Research to Atomic-Level video
Preview image for Under the Titan Lens: Microscope Takes Research to Atomic-Level video

Under the Titan Lens: Microscope Takes Research to Atomic-Level

Remote Training and Collaboration

  • Zoom screen-share from both the TEM laboratory web camera and instrument control monitors
  • Huskycast (Panopto) recording of lab space, TEM lab camera, and instrument control monitors

Ex situ and In situ Capabilities

Conventional TEM (CTEM)

Accelerating Voltages from 80–200 kV

  • High Contrast images (desired for standard biological TEM samples) at Low Magnification mode (field of view from 100 microns to 1 micron)
  • High Resolution TEM (HRTEM) to identify lattice spacings less than 0.15 nm
  • Crystallographic phase analysis in Diffraction mode:
    • Selected Area Electron Diffraction (SAD) from a minimum area of 200 nm in diameter
    • Convergent-beam Electron Diffraction (CBED) analysis: e.g. determination of crystal system, Bravais lattice, point, and space groups of crystals larger than 50 nm in size
    • Nanobeam Electron Diffraction (NBD) analysis (Convergent semi-angle less than 0.1 mrad)
Array of silicon atoms
Columns of Si atoms in the 110 orientation. Note the separation between the individual atoms creating the so-called Si “dumbbells”.

Probe Corrected Scanning Transmission Electron Microscopy (STEM)

Accelerating Voltages from 80–200 kV

  • Z-contrast images by High-angle Annular Dark-Field (HAADF) (Fischione HAADF detector)
  • Atomic resolution Z-contrast imaging by HAADF-STEM
  • Annular Dark-Field (ADF), low angle ADF, and Bright-Field STEM imaging (useful for grain size, dislocations and defect imaging)
  • Micro-probe STEM with larger depth of focus

ChemiSTEM Super X-ray Energy Dispersive Spectroscopy

Four X-ray Detectors, FEI/ThermoFisher

  • Fast elemental analysis and elemental mapping up to very high spatial resolution (combined with HAADF-STEM)
  • Clear and low background XEDS spectrum using the beryllium specimen holder.
  • 3-dimension elemental analysis reconstruction (STEM EDS Tomography)

Electron Energy Loss Spectroscopy (EELS)

GIF Quantum Dual EELS System

  • Elemental analysis from Li–U at very high spatial resolution (combined with HAADF-STEM)
  • Elemental mapping and phase mapping by STEM-EELS spectrum imaging 
  • Low-loss and core-loss EELS with energy resolution of 0.9 eV
  • Oxidation state analysis by core-loss EELS
  • Thickness measurement

Energy Filtered TEM (EFTEM)

GIF Quantum Dual EELS System

  • Elastic electron imaging to enhanced contrast of TEM images and diffraction patterns
  • Thickness and elemental mapping (in EFTEM mode) and EFTEM spectrum imaging

Ex situ TEM Sample Holders

  • Single Tilt holder (FEI/ThermoFisher)
  • Beryllium tip Double Tilt holder (FEI/ThermoFisher)
  • Room temperature tomography holder (Fischione) for both TEM and STEM tomography

In situ TEM Sample Holders

  • Electrical bias and Heating stage NanoEx holder (FEI/ThermoFisher)
  • Nanoindentation holder (Nanofactory)
  • Poseidon 510 liquid cell holder (Protochip)

The video is created from 130 images (commonly known as slices) of a conglomerate of Li-ion battery cathode particles. Sample is courtesy of Professor Steve Hackney.

Watch STEM Tomography of Li-ion Battery Cathode Particles video
Preview image for STEM Tomography of Li-ion Battery Cathode Particles video

STEM Tomography of Li-ion Battery Cathode Particles

Training

Courses

Michigan Tech offers many undergraduate and graduate courses related to materials characterization.

One of these courses offers direct, hands-on training in transmission electron microscopy.

MSE 5550 Course Topics

  • Lenses and Apertures (ray diagram)
  • Introduction to the TEM
  • Lenses and Apertures (condenser system)
  • TEM basic alignments and condenser aperture system
  • Lenses and Apertures (imaging/diffraction mode)
  • Lenses and Apertures (three major defects)
  • Parallel illumination and Objective Aperture
  • Lenses and Apertures (depth of focus/field)
  • Scattering (scattering cross section)
  • Electron diffraction, image formation and contrast
  • Scattering (Fresnel fringes)
  • Scattering (image formation and contrast)
  • S-TEM
  • Elastic Scattering vs. Inelastic Scattering
  • Selected area electron diffraction (“powder” diffraction)
  • X-ray Spectroscopy, XEDS
  • Diffraction
  • STEM imaging and XEDS
  • XEDS, EELS
  • EELS
  • STEM imaging and EELS
  • Phase Contrast Images
  • Phase contrast imaging
  • High Resolution TEM (transfer function)
  • High Resolution TEM (Scherzer defocus)
  • HRTEM imaging
  • Crystallography and Diffraction (Bragg’s law)
  • Crystallography and Diffraction (reciprocal lattice)
  • Zone Axis electron diffraction (SAD)
  • Crystallography and Diffraction (diffraction patterns)
  • Crystallography and Diffraction (indexing DPs)
  • Diffraction from Small Volumes
  • Dynamical Diffraction (effective excitation error)
  • Convergent beam electron diffraction (CBED)
  • Dynamical Diffraction (thickness/bending effect)
  • Convergent Beam Electron Diffraction
  • Liquid phase TEM imaging

Other Courses