TEM/ STEM – EDS/EELS
TEM/ STEM – EDS/EELS
Transmission Electron Microscopy/Scanning Transmission Electron Microscopy
Transmission Electron Microscopy (TEM) is an imaging technique in which forward scattering of a high energy electron beam transmitted through a sample is used to form images from regions as small as several nanometers. The Cerium Labs TEMs can achieve point resolutions better than 0.2 nm allowing lattice imaging of crystalline and polycrystalline materials. TEM can be used in a wide variety of imaging applications from atomic scale metrology of thin films and nanostructures to the characterization of inclusions, defects, and precipitates. Strain-contrast imaging can be used to reveal dislocations, stacking faults, and other crystalline imperfections. In electron diffraction mode, diffraction patterns can be acquired and analyzed to determine the structural phase of a material or epitaxial relationships at interfaces.
Scanning Transmission Electron Microscopy (STEM) is an analytic technique in which a small (~1 nm) electron probe is scanned on a sample to generate characteristic signals that are measured by various detectors. STEM EDS analysis collects X-rays from this process to provide spectra of local composition, line scans of layered materials, and elemental maps of complex structures. STEM ADF imaging collects electrons scattered at high angles to form high-contrast images that reveal small differences in composition, such as those found in layered III-V materials. Both TEM and STEM modes can be used with an image filter/electron spectrometer attached to the microscope to yield EFTEM images and EELS data for mapping of low-Z elements such as C, N, O, and F.
- JEOL JEM2010 S/TEM operated with a thermionic emission gun at accelerating voltages of 100 kV-200 kV.
- PHILIPS CM300 S/TEM operated with a field emission gun at accelerating voltages of 200 kV-300 kV.
- Noran EDS system
- Gatan Image Filter
- JEM-ARM200F S/TEM operated with a field emission gun at accelerating voltages of 80 kV-200 kV.