SCANNING ELECTRON MICROSCOPY
I. SEM & Array Tomography
II. cryo-FIB/SEM
II. AFSEM: In-situ AFM in a SEM
I. SEM & Array Tomography
The Scanning Electron Microscope (SEM) produces an image that resembles one with three-dimensional features. Like the TEM, it utilizes electrons to generate an image, but it scans through the surface of the material, generating secondary electrons from the sample that are then detected by a sensor (cells to whole organisms can be scanned). SEM allows the operator to observe the fine details of the morphology and surface of the samples with a great depth of field.
Resources
- Hitachi TM-1000: Bench-top scanning electron microscope to visualize surface structures
- Array Tomography workflow
Applications
- Enable 3D reconstruction and analysis of samples with nanometer resolution by means of scanning electron microscopy technique.
II. Cryo-FIB/SEM
Focused Ion Beam – Scanning Electron Microscopy (FIB-SEM) is based on a slice-and-view approach to generate stacks of 2D EM images. The data can be reconstructed in 3D and provide a comprehensive and accurate view on the subcellular organisation of cells and tissues, at a resolution in the nm range. A FIB-SEM is a dual beam setup with an electron column for imaging and an ion column that is used as a slicing-tool. A beam of gallium ions is used to scan over the sample surface milling away a thin layer in a very precise manner. With this approach, layers as thin as 5 nm can be removed. Although other 3D EM imaging modalities are available (tomography, serial-sectioning TEM), FIB-SEM is favourable for its throughput in image collection.
Resources
- Cryo-FIB/SEM Aquilos (Cryo-lamella preparation and crystal thinning)
- FEI Quanta 200 3D Dual Beam FIB
- Polaron cryo stage and transfer unit
- EDX detector
Applications
- Cross sectioning and imaging/chemical characterization of biological materials
III. AFSEM: In-situ AFM in an SEM
The AFSEM is an add-on at the field emission SEM or dual-beam FIB and allows topographic characterization correlated with imaging and chemical analysis without removing the sample from the SEM. The maximum size to be investigated in one single measurement is 30 x 30 µm2. The AFSEM allows AFM investigations unter high vacuum conditions.
Resources
- GETec Microscopy AFSEM with low-noise self-sensing cantilevers
- Available at the FEI Quanta 250 FEG field emission SEM and at the FEI Quanta 200
- 3D dual beam FIB
Applications
- Any kind of materials, where topological information has to be combined with SEM imaging and/or chemical characterization by EDX