Electron Microscopy, Nanoscopy, and Scanning Micro‐ and NanoanalysisUpdate based on the original article by Vladimir Oleshko, Renaat Gijbels and Severin Amelinckx,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

Abstract

The article considers the history and stages of development of electron microscopy (EM) and scanning microanalysis, including theoretical aspects of electron beam–solid interactions, instrumentation, methodology of particular techniques and image analysis, sample preparation, and some typical applications as well. Major classes of EM techniques, i.e. stationary beam (transmission) and scanning beam EM methods, analytical electron microscopy (AEM), in situ EM, holography, and tomography are overviewed. In AEM, several imaging, diffraction, and analytical modes are integrated in a design to provide analytical synergism having obvious advantages over any single instrument. The subject of EM is to determine the morphology, crystallinity, defect structure, phase and elemental compositions, and electronic properties of a material using the focused electron beam and signals generated in the course of its interaction with the specimen. Various electron–specimen interactions generate a great deal of structural and analytical information in the form of emitted electrons and/or photons and internally produced signals, such as elastically and inelastically scattered electrons, Auger electrons (AEs), X‐rays, and cathodoluminescence (CL), which can be analyzed in different operating modes. Imaging of solid materials is essentially due to elastic scattering (diffraction) of electrons by the periodic arrangement of atoms in crystals (diffraction contrast) and/or interference of several diffracted and transmitted beams (phase contrast). High‐resolution imaging in scanning transmission mode is possible by using incoherently scattered electrons (Z‐contrast). Inelastic interactions form the basis for all chemical analytical techniques (energy‐dispersive (EDS) and wavelength‐dispersive (WDS) X‐ray spectroscopy, electron energy‐loss spectroscopy (EELS) energy‐filtering transmission electron microscopy (EFTEM), AE‐, and CL‐spectroscopy). The introduction of aberration‐corrected and monochromatic electron optics during the last decade opened a new era of nanoscopy and nanoanalysis at sub‐0.1 nm lateral resolution and sub‐electronvolt energy resolution levels with improved signal‐to‐noise ratio (SNR). Basic data characterizing the current state‐of‐the‐art and trends in development of electron nanoscopy and nanoanalysis are presented.