Applications and practical uses - what the SEM can do
Scanning electron microscopy is a remarkably versatile technique. There are many different types of SEMs available, tailored to specific needs. With SEM one can:
- Image morphology of samples (e.g. view bulk material, coatings, sectioned material, foils, even grids prepared for transmission electron microscopy).
- Image compositional and some bonding differences (through contrast and using backscattered electrons).
- Image molecular probes: metals and fluorescent probes.
- Undertake microand nano lithography: remove material from samples; cut pieces out or remove progressive slices from samples (e.g. using a focussed ion beam).
- Heat or cool samples while viewing them (while possible in many instruments it is generally done only in ESEM or during Cryo-scanning electron microscopy).
- Wet and dry samples while viewing them (only in an ESEM)
- View frozen material (in an SEM with a cryostage)
- Generate X-rays from samples for microanalysis (EDS; WDS) to determine chemical composition.
- Study optoelectronic behaviour of semiconductors using cathodoluminescence
- View/map grain orientation/crystallographic orientation and study related information like heterogeneity and microstrain in flat samples (Electron backscattered diffraction).
- Electron diffraction using electron backscattered diffraction. The geometry may be different to a transmission electron microscope but the physics of Bragg Diffraction is the same