The Scanning Electron Microscope (SEM) is one of the most versatile and widely used tools in general of modern science and particularly of nanotechnology which allows the study of both morphology and composition of biological and physical materials. Scanning electron microscope can scan the surface of a sample with a finely focused electron beam to produce an image from the beam-specimen interactions detected by a wide array of detectors. There are a wide range of detectors from secondary electron detectors to give surface information to backscattered detectors for compositional information that work in high or low vacuum modes. Accessories such as energy dispersive spectrometry (EDS), wavelength dispersive spectrometry (WDS) and electron backscattered diffraction (EBSD) can also be added to any SEM to enable chemical data collection. All systems can also accommodate cryo stages to look at frozen materials and some can accommodate hot or cold stages for watching dynamic experiments. By scanning an electron probe across a specimen, high resolution images of the morphology or topography of a specimen, with great depth of field, at very low or very high magnifications can be obtained. Compositional analysis of a material may also be obtained by monitoring secondary X-rays produced by the electron-specimen interaction. Thus detailed maps of elemental distribution can be produced from multi-phase materials or complex, bio-active materials. Characterization of fine particulate matter in terms of size, shape, and distribution as well as statistical analyses of these parameters, may be performed.There are many different types of SEM designed for specific purposes ranging from routine morphological studies, to high-speed compositional analyses or to the study of environment-sensitive materials. Three particular types of SEM can be combined to provide a powerful analytical approach for many research or quality-control applications.
Current worldwide SEM manufacturers: