The electron microscope is classified by its principle and structure into two types: the transmission electron microscope (TEM) and scanning electron microscope (SEM). The principle of the TEM is to obtain a transmitted electron image or an electron diffraction pattern from a specimen, by magnifying an image or a pattern formed by electrons transmitted through the specimen. The principle of the SEM is to obtain a secondary electron image generated from the specimen surface by 2-dimensional electron beam scanning. The TEM and the SEM are capable of not only magnifying an image of fine structure but also making elemental analysis of small areas on the specimen. Therefore, both instruments are widely used as indispensable analytical tools in the field of material research such as metals, semiconductors, inorganic materials and polymers. In this article, the methods of image observation and elemental analysis, and application data obtained with both TEM and SEM are introduced.
