Final answer:
An ultramicrotome is utilized to create sections thinner than 100 nm for TEM, following the process of dehydration and embedding of the specimens.
Step-by-step explanation:
The device used to prepare sections thinner than 100 nm for transmission electron microscopy (TEM) is called an ultramicrotome. The process of preparing samples involves embedding cells in plastic resin, dehydrating them with ethanol, and then slicing them using the ultramicrotome.
The thin sections are then fixed onto grids and stained with heavy metals such as uranyl acetate or osmium tetroxide to enhance electron density.