Transmission Electron Microscopy (TEM)

In a transmission electron microscope (TEM), a thin specimen (ideally ≤ 100 nm) is exposed to a high-energy (typically 60 - 300 keV) electron beam. Images generally contain contrast that may be due to crystallinity, atomic mass, or thickness variations within the sample. Crystallographic information can also be obtained from diffraction patterns. We can also collect elemental and chemical state maps via analysis of 1) emitted x-rays (Energy Dispersive Spectroscopy – EDS) or 2) the energy loss of electrons that have gone through the specimen (Electron Energy Loss Spectroscopy – EELS).  All of our micrcosopes can also be operated in STEM mode which may be better in some cases for beam sensitive or low contrast samples.

 
Instrumentation
               
TEMs Source kV Min. Resolution (Å) Min. Probe Size (Å) STEM EDS EELS EFTEM
Tecnai G2 20 XTWIN LaB6 80, 200 0.24 10 * * * *
Talos F200X XFEG 80, 200 0.12 1.6 * * (SuperX EDS)    
FEI Titan3 G2* XFEG 60, 80, 200, 300 0.7 0.7 * * (SuperX EDS) * *
 
Types of sample holders available:
  • Cryo-holder and cryo-transfer holder for looking at frozen hydrated samples.
  • In-situ heating and biasing:Protochips Aduro 500 (link to in-situ page)
  • In-situ liquid and electrochemistry:Protochips Poseidon 510 (link to in-situ page)
  • Fischione tomography (+/- 70° tilt)
Typical Applications
  • Microstructure and nanostructure: size and morphology
  • Cross-section analysis (layer thickness, interface quality)
  • Crystal structure determination through electron diffraction
  • Defect analysis (dislocations, stacking faults, etc.)
  • High resolution images (~0.2 nm resolution)
  • Chemical information – composition and bonding (EDS, EELS) from single points, line scans or maps
  • Energy filtered imaging (EFTEM)
  • Z-contrast imaging using high angle annular dark field (HAADF)
Application Examples
  • Z-Contrast Imaging of InAs Quantum Wells in GaAs/AlAs Quantum Wells
  • Nanocrystalline Diamond in Ru-Doped DLC Films
  • XPS and HR-TEM Analysis of High k Thin Films
Training

New users will generally start training first on the Tecnai.  Please see individual instrument pages for details regarding training.  Users can also get training on how to prepare their own samples with the assistance of MCL staff.

TEM analysis and research support

For users with a limited number of samples that do not wish to get trained on the TEM, the TEM staff scientists can help to determine the proper techniques, acquire and analyze the data that is needed for your samples.