Center for Electron Microscopy (ZELMI)

Preparation for transmission electron microscopy

© ZELMI TUB
© ZELMI TUB

Investigations using TEM place special demands on the samples. On the one hand, they must be electron-transparent, i.e. very thin, and on the other hand, they must be dry, vacuum-stable and not change under electron bombardment.
Depending on the material and the task, the maximum sample thicknesses can vary, but should not be significantly thicker than 100 nm in order to obtain good test results.
For atomic resolution, the sample thicknesses should be less than 20 nm.

Cutting with the wire saw

Plan-View preparation incl. ion dilution

Suitable for the following problem:

  • Examination of material samples
  • Highest resolution investigations
  • Crystallographic investigations
  • Elemental analysis

Requirements for the sample:

  • stable sample
  • no powder

to be considered:

  • high time requirement
  • residual amorphization, possibly artifact formation

 

Powder preparation

Suitable for the following problem:

  • Examination of powder
  • Maximum dissolution analysis
  • Elemental analysis

Sample requirement:

  • Powder particle size from 0.5 to 100 µm

to be considered:

  • high time requirement
  • residual amorphization and possibly artifact formation

 

Cross-section preparation incl. ion dilution for TEM

suitable for the following research question:

  • Investigation of interfaces
  • Investigation of growth directions
  • Highest resolution investigations
  • Elemental analysis
  • Crystallographic investigation

Requirements for the sample:

  • stable layer
  • stable interface

to be considered:

  • high preparation effort
  • residual amorphization and possibly artifact formation

 

 

Preparation of suspensions/microemulsions/colloidal solutions

Suitable for the following research question:

  • Investigation of morphology
  • Highest resolution investigations
  • Size distribution
  • Tomographic investigations
  • Data acquisition for 3D reconstruction
  • Elemental analysis

Sample requirement:

  • Powder particle size up to 500 nm

 

 

Flue gas preparation

Suitable for the following problem:

  • Measurement of air pollution

Sample requirement:

to be observed:

  • Sampling on site

 

Ultramicrotomy

Suitable for the following problem:

  • Cross-section or longitudinal section of biological specimens and solids.
  • sectioning for 3D reconstruction
  • for samples that cannot be prepared classically

Sample requirement:

  • can be cut with diamond
  • if necessary temperature resistant up to 60 °C for 48 hours (embedded samples)
  • if necessary water or solvent resistant

to be noted:

  • Preparation time up to 2 days

 

 

FIB preparation

  • To cut fine lamellae from compact specimens for TEM examinations, the FIB is used.

Cross-section preparation with the FIB