-The earliest known work describing the concept of a scanning electron microscope was by M. Knoll(1935).
•M. Von Ardenne(1938) constructed a scanning transmission electron microscope(STEM) by adding scan coils to a transmission electron microscope.
•The first commercial scanning electron microscope became available in 1965 by Cambridge scientific instruments.
Scanning Electron Microscope
-A type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the sample’s surface topography and composition.
-Image magnification can be up to 10 nanometers.
-Although SEMs are large, expensive pieces of equipment, they remain popular among researchers due to their wide range of applications and capabilities, including the high resolution, three dimensional, detailed images they produce.
Strengths
•There is arguably no other instrument with the breadth of applications in the study of solid materials that compares with the SEM.
•SEM is critical in all fields that require characterization of solid materials.
•Modern SEMs generate data in digital forms, which are highly portable.
Limitations
•Sample must be solid and they must fit into the microscope chamber.
•Samples likely to outgas at low pressures are unsuitable for examination in conventional SEM’s.
Advantages
•Advantages of a Scanning Electron Microscope include its wide-array of applications, the detailed from different detectors.
•SEM are also easy to operate with the proper training and advances in computer technology and associated software make operation user-friendly.
•This instrument works fast, often completing SEI, BSE and EDS analyses in less than five minutes. In addition, the technological advances in modern SEMs allow for the generation of data in digital form.
