Fluctuation electron microscopy (FEM), originally called Variable Coherence Microscopy before decoherence effects in the sample rendered that naming moot, is a technique in

electron microscopy An electron microscope is a microscope that uses a beam of electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing i ...

that probes nanometer-scale or "medium-range" order in disordered materials. The first studies were performed on

amorphous In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is a characteristic of a crystal. The terms "glass" and "glassy solid" are sometimes used synonymousl ...

Si (Treacy and Gibson 1997) and later on hydrogenated amorphous silicon.

References

Electron microscopy techniques {{CMP-stub