Transmission Electron Microscope (TEM)

A microscope that produces an image by using electron beams to pass through the specimen, making examination of internal features at high magnifications possible.

Bright Field Imaging

A imaging mode in a TEM that uses only Unscattered Electrons to form the image. Contrast in such an image is due entirely to thickness and density variations in a sample.

Convergent Beam Electron Diffraction

An electron probe is tightly focused on a specimen and the resulting pattern of diffracted electrons is observed. The patterns contains information on the crystal symmetry and atomic and electronic structure of the sample.

Regions as small as 0.2 nm may be examined.

Dark Field Imaging

Using a single diffracted beam to form the image in a TEM. This causes all regions of the specimen not of the same crystal structure and orientation as the region which produced the diffracted beam to be represented as very dark in the final image. Thus allowing phase differentiation visually in the TEM.

Selected Area Electron Diffraction

An aperture is used to define the area from which a diffraction pattern is formed in a TEM specimen. The resulting patterns contain information about phases present (lattice spacing measurement) and sample orientation.

See also: Electron Microscope, Microscope, Microscopy, Scanning Electron Microscope.

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Subjects: Instrumentation