Cell Biology Practice Test: Techniques in Cell Biology - SEM and AFM — Flashcards

Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are two techniques used for nanoscale sample analysis. They are complementary techniques.

Some differences between SEM and AFM are:
Magnification: SEM provides magnification in two dimensions, while AFM provides magnification in three dimensions.
Height measurement: Users can directly measure the height of a sample feature from an AFM image. Typically, the SEM sample must be cross-sectioned to obtain the height of a feature.
Surface structure: AFM is capable of producing a three-dimensional topography using just a single scan on atomically smooth surfaces. AFM also provides a greater level of detail for these surfaces.
Cost: SEMs are generally more expensive than AFM instruments.
Elemental analysis: SEM can provide elemental analysis using X-ray detection, whereas the AFM can provide compositional information based on physical properties. 

AFM has several advantages over the SEM:
AFM provides a three-dimensional surface profile, unlike the electron microscope, which provides a two-dimensional projection or a two-dimensional image of a sample.
AFM can produce a three-dimensional topography using just a single scan on atomically smooth surfaces.