Electron Microscopy: SEM, TEM Notes

Scanning Electron Microscopy (SEM)

• Purpose: Produces images by scanning a surface with an electron beam to reveal surface morphology and topography.

• Imaging output: Surface-level information (3D-like appearance due to shading and perspective), rather than internal structure.

• Magnification: Up to $\sim2 \times 10^6$ (2 million times).

• Capabilities: Can capture 2D images of surface features; in some setups, it can provide pseudo-3D representations of surface topology.

• Combined techniques: Morphology data is often complemented with elemental analysis via EDS (see EDS section).

Transmission Electron Microscopy (TEM)

• Purpose: Produces images that reveal the internal structure of a sample by transmitting electrons through an ultra-thin specimen.

• Imaging output: Internal microstructure, crystallography, defects, grain boundaries, etc., viewed in projection (2D).

• Magnification: Up to $\sim5 \times 10^7$ (50 million times).

• Sample thickness requirement: Typically requires very thin specimens, often