Electron Microscopes
Scanning Electron Microsopes (SEM)
The Centre for Material Analysis has three field emission scanning electron microscopes (FESEM). SEM imaging is conducted by scanning the electron beam across the samples surface and detecting the emitted secondary electrons (SE) (high-resolution images) or the backscatter electrons (BSE) (mass contrast images).
SEM imaging resolution is about one nanometer. All the University’s FESEMs are equipped for chemical and crystallographic analysis with energy-dispersive x-ray spectroscopy detectors (EDS) and electron backscatter diffraction cameras (EBSD), respectively.
SEMs of the University of Oulu are widely utilized in the materials science. Two the FESEMs are equipped for mineral liberation analysis (MLA) of geological samples.
Electron Probe Microanalyzer (EPMA)
An electron probe microanalyzer (EPMA) is an electron microscope dedicated for an accurate elemental analysis. The EPMA is equipped with the wavelength dispersive x-ray spectroscopy (WDS) detectors and the energy-dispersive x-ray spectroscopy (EDS) detector for the accurate qualitative and quantitative elemental analysis. The EPMA is a non-destructive analysis method, and it can detect very small elemental concentrations.
The EPMA can be widely utilized in mineralogy, metallurgy, and other materials research.
FIB-FESEM
A focused ion beam-field emission scanning electron microscope (FIB-FESEM) is an instrument with an ion gun and an electron microscope integrated in the same platform. The FIB-FESEM is a multipurpose research device suitable for nanostructure fabrication, imaging, and analysis.
Thin samples for the transmission electron microscope (TEM) can be prepared with very high precision by using the FIB-FESEM system.
Transmission Electron Microscope (TEM)
A transmission electron microscope (TEM) is a research instrument for high-resolution imaging and analysis of material samples. Operation of the TEM is based on an electron beam penetrating the sample. The best imaging resolution is 0.1 nm.
Crystal structure and chemical composition of the sample can be analyzed by using different electron diffraction and spectroscopy methods.
TEM samples need to be very thin (< 100 nm), which makes the method particularly suitable for the analysis of nanoparticles and fibers. Thins samples can be prepared from bulk materials for example by using the FIB-FESEM system.