Question

How would you characterize a material someone hand to you that you have no idea what it is using SEM?

Answer 1

Scanning Electron Microscopy (SEM)

SEM is generally used to investigate surface topography. A primary electron beam with 1 – 10 keV is focused to 1-10 nm and scanned over the surface. The secondary electron yield or other quantities are used to modulate a cathode ray tube (CRT).

When a sample is bombarded with an electron beam, secondary electrons are generated, which is used to analyse the surface topography.

Also there may be back scattered electrons which are those electrons reflected from the sample.

From these interactions a particular signal is obtained for each sample and also gives the image of the particle in nanometer dimension.