Characteristic energy loss peaks (similar to EDS) allow us to identify the elements present. With EELS we analyse the amount of energy lost by the electrons after they have passed through the sample. EDS can be conducted from the micron- to the nano-scale.īack to top Electron energy-loss spectroscopy (EELS)Įlectron energy-loss spectroscopy (EELS) EELS is another microanalysis technique that provides complementary information to EDS. This provides a qualitative analysis of the elements present and, with further analysis, a quantitative composition can be determined. When the electron beam hits the sample, X-rays that have characteristic energies for each element are generated. SAED patterns can be obtained on all of the Centre’s TEMs.īack to top Energy-dispersive X-ray spectroscopy (EDS/EDX/EDXS)ĮDS is a microanalysis technique allowing us to determine the composition of the sample. Similar to HRTEM, it can be used to identify crystal phases and their orientations, though not on such a small spatial scale. The spacings and orientations of the diffraction spots can be interpreted in terms of the planar spacings and orientations in the sample. SAED patterns provide crystallographic information from selected regions of the sample from the micron to the ~100nm scale. The best results will be obtained on the FEI Titan.īack to top Selected-area electron diffraction (SAED/SAD) HRTEM images can be obtained on the FEI Titan and JEOL 2100. As a crystallographic tool it can be used to identify crystal phases and orientations. It can be used to investigate the crystallinity of the sample, including identification of lattice planes and some defects. HRTEM is a phase-contrast imaging technique, which makes it possible to obtain images with atomic resolution. Thus, regions of high intensity represent strong scattering. In DF mode, the image is formed with electrons scattered in a specific direction, usually as a result of diffraction from a particular atomic plane or planes. In BF images, areas of high scattering appear dark indicating regions of high mass, thickness or strong diffraction effects. The TEM has two standard imaging modes – bright field (BF) and dark field (DF). Information can also be obtained on the composition and chemistry of the sample using a range of optional microanalysis techniques. The image formed shows variations in the scattering of the electrons by the sample related to the mass of the atoms, the thickness of the sample or the orientation of the sample (if it is crystalline). Transmission electron microscopy (TEM) involves a beam of high-energy electrons passing through a thin sample, typically about 100nm thick.

Tem saed pattern analysis