Electron Optics Facility

STEM

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

FEI 200kV Titan Themis STEM

Request Sample Intake

Fill out the ACMAL/STEM - Titan Themis - Intake Samples Form before using the instrument. Include administration details, high tension required, intended techniques, and sample identification. ACMAL staff will then follow-up to schedule a time for analysis. If you are an authorized user, make reservations as usual and then submit the form.

Intake Sample 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 six specialized specimen holders that extend the STEM utility.

A view of the S-TEM set up.

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.