Scanning Electron Microscopy (SEM)

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SEM rasters a focused electron beam over the sample surface and detects secondary or backscattered electrons [3].

  • Resolution: 1–20 nm, depending on instrument and sample.

  • Contrast mechanisms:

    • Secondary electron (SE) images show surface topography.

    • Backscattered electron (BSE) images show compositional (atomic number) contrast — heavier elements appear brighter.

  • Applications: particle morphology, grain structure, electrode cross-sections, coating thickness.

  • Typical artifacts: charging effects (non-conductive samples), curtaining (FIB cross-sections), beam damage, low signal-to-noise at high magnification.

See also