TEM and SEM are the same microscopy techniques.

A transmission electron microscope (TEM) is a microscope that uses a beam of electrons to create a highly magnified image of a specimen. The specimen is usually a thin section or suspension on a grid that is less than 100 nanometers thick.  TEMs can magnify objects up to 2 million times. Unlike optical microscopes, which use light in the visible spectrum, TEMs can magnify nanometer structures up to 50 million times. This allows TEMs to reveal details at the atomic scale.  TEMs are used to view thin specimens, such as tissue sections and molecules. They are also used to image the internal... Show more

A transmission electron microscope (TEM) is a microscope that uses a beam of electrons to create a highly magnified image of a specimen. The specimen is usually a thin section or suspension on a grid that is less than 100 nanometers thick. 
TEMs can magnify objects up to 2 million times. Unlike optical microscopes, which use light in the visible spectrum, TEMs can magnify nanometer structures up to 50 million times. This allows TEMs to reveal details at the atomic scale. 
TEMs are used to view thin specimens, such as tissue sections and molecules. They are also used to image the internal structure of solids. 
TEMs were first developed in 1931 by German scientists Max Knoll and Ernst Ruska. They are now commonly used in science and engineering to study micro and nanoparticles.

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