Scanning electron microscope (SEM), TEM

1. What is Microscopy?
Microscopy is any technique for producing visible
images of structures or details too small to otherwise
be seen by the human eye.

2. Why Microscopy?
• In order to effectively study something or build something it
is important to see exactly what it is we’re doing.
• As the things we are interested in get smaller and smaller we
need much better, meaning more powerful microscopy.
• Eventually this will necessitate advances in the physics.

3. Microscopic Techniques
1. Optical microscopy
Conventional light microscopy, Fluorescence microscopy
2. Electron microscopy
Scanning electron microscopy (SEM), Transmission electron
microscopy (TEM), High resolution transmission electron microscopy (HTEM)
3. Scanning probe microscopy
Scanning tunneling microscopy (STM), Atomic force microscopy (AFM)

4. Conventional Optical Microscopy
This is an optical instrument containing one or more lenses that produce
an enlarge image of an object placed in the focal plane of the lens.
Resolution limit: submicron particles approaches the wavelength of visible light
(400 nm to 700 nm).
1. Transmission: beam of light passes through the sample
e.g. Polarizing or petrographic microscope
Samples are usually fine powder or thin slices (transparent)
2. Reflection: beam of light reflected off the sample
e.g. Metallurgical or reflected light microscope
Surface materials especially opaque ones

12. Electron Microscopy

16. Difference between OM and EM

30. Different uses of TEM

31. Scanning Electron Microscope (SEM)

45. Difference between TEM and SEM