Electron microscopy uses an electron beam to create an image of a sample. Because of this an electron microscope has a much greater resolving power than a light microscope and is capable of much highermagnifications (up to 2 million times).
There are two types of electron microscopes - transmission electron microscopes (TEM) and scanning electron microscopes (SEM). SEM shows the specimen surface, TEM is used to reveal structures of thin samples or thin sections. TEM images are two-dimensional projections of 3D objects. Electron microscopy can be used to investigate the microstructure of a wide range of biological and inorganic specimens providing morphologic and crystallographic information. The EM operates under vacuum which means the samples are placed in a vacuum system during analysis. Therefore, some samples need to be specially prepared to withstand the environment inside an electron microscope.