In scanning electron microscopy (SEM) a focused electron beam is scanned across the surface of the specimen eliciting the emission of secondary electrons that generate an image showing topographical detail.Depending on how deep within the sample the electrons are generated, information about the sample elemental composition can also be gathered.
Most modern scanning electon microscopes will likely use several types of detectors to collect all different signals generated by the electrons and the sample. This allows the user to optimally detect, capture, collect and display other analytical and imaging modes as desired (such as energy dispersive spectroscopy) enabling mapping of different elemental species within the sample’s area of interest.
As with TEM samples, SEM samples need to withstand vacuum. Therefore they also require specific preparation methods.
SEM is used to provide images from low to very high magnification (200X – 1.106X) with resolution up to 6Å, depending on the microscope specification.
