Transmission Electron Microscopy (TEM) is a powerful imaging technique used to observe the internal structure of materials at the atomic level. It works by transmitting a beam of electrons through a thin sample, allowing scientists to visualize the arrangement of atoms and identify defects or phases within the material. TEM is widely used in fields such as materials science, biology, and nanotechnology. The technique requires samples to be extremely thin, typically less than 100 nanometers, to allow electrons to pass through. TEM can provide high-resolution images and detailed information about the sample's composition, making it an essential tool for researchers studying materials like metals, semiconductors, and biological specimens.