Scanning Electron Microscopy (SEM) Characterization

Having access to two types of scanning electron microscopy systems allows Innovatech Labs to meet the demands of the most challenging materials characterization projects. The two types of scanning electron microscopes (SEM) available through Innovatech Labs are - Variable Pressure SEM and Field Emission SEM. 

Both SEM's are equipped for digital image capture.  Magnification for all imaging is calibrated to a traceable standard.  Image analysis for coating thicknesses, grain size determinations and particle sizing can be applied to the saved images.

Qualitative elemental analysis, standardless quantitative analysis, x-ray line scans and mapping can be performed on both of the SEM systems.

Below, you will find more information on how SEM/EDS works and more information about the two different types of systems available. 

You are always welcome to contact analytical laboratory Innovatech Labs to discuss your individual needs at 888-740-5227or by email.

SEM/EDS -

Scanning Electron Microscopy / Energy Dispersive Spectroscopy

Scanning electron microscopy (SEM) is a method for high resolution surface imaging.  The SEM uses electron for imaging, much as light microscopy uses visible light.  The advantages of SEM over light microscopy include greater magnification (up to 100,000X) and much greater depth of field. Different elements and surface topography emit different amounts of electrons, due to this the contrast in the electron micrograph (picture) is representative of surface topography and composition.

Energy dispersive spectroscopy (EDS) measures the number of x-rays produced by a solid sample when irradiated by electrons versus the energy of these x-rays.  The EDS technique identifies and quantifies the element constituents of the sample.

Variable Pressure SEM

The variable pressure SEM (VPSEM) is a relative newcomer to the microscopy world, but has become the workhorse instrument in many analytical laboratories.  By varying the pressure in the vacuum chamber, these instruments can operate at moderately high magnification (50,000X on conductive samples or at lower magnification nonconductive or wet samples.  Traditionally, nonconductive samples had to be coated prior to SEM examination, and it was not possible to image wet samples at all.

The ability to image nonconductive samples without coating is a great advantage for nondestructive evaluation and for performing microanalysis without the distraction of carbon or metal coating.  The VPSEM also has a spacious sample chamber that can accommodate large and irregularly-shaped specimens.

Field Emission SEM

With a brighter electron source and smaller beam size than the VPSEM, the field emission SEM (FESEM) increases the useful magnification range for observation and imaging up to 500,000X.

A second advantage of FESEM is that high resolution imaging can be performed with very low accelerating voltages.  At low voltage, very fine features are more readily observed, especially for low-density materials.  Low voltage SEM examination is ideal for imaging polymer materials and thin films.

Comparison of V.P. SEM and F.E. SEM Applications