The document provides an overview of transmission electron microscopes (TEM). It discusses the history of TEMs, which were invented in the 1930s. It describes how TEMs work using a beam of electrons rather than light to image samples at much higher magnifications than light microscopes. Sample preparation for TEMs is also outlined, including thinning, dimpling, and ion milling techniques to create electron-transparent samples. TEMs can provide information about a sample's topography, morphology, composition, and crystal structure at magnifications over 10,000x.

1. Transmission Electron
Microscope (TEM)
Student Name: Noman Chowdhury
Student ID:0416023709
Supervisor: Dr. Abu Bin Imran
Bangladesh University of
Engineering & Technology

2. CONTENT
• History
• Working principle
• Sample preparation

3. Electron Microscopy
What are electron microscopes?
Electron Microscopes are scientific instruments that use a beam
of highly energetic electrons to examine objects on a very
fine scale which yield the following information:
1. Topography : The surface features of an object.
2. Morphology : The shape and size of the particles.
3. Composition : The elements and compounds that the object is
composed of and the relative amounts of them.
4. Crystallographic Information : How the atoms are arranged in
the object.

4. History of electron microscope
• Max Knoll and Ruska, first TEM in 1931
• Idea and first images published in 1932
• By 1933 they had produced a TEM
with two magnetic lenses which gave
12 000 times magnification.
google
Ernst Ruska:
Nobel Prize in physics 1986
Electron Microscope Deutsches
Museum, 1933 model

5. Why Electron Microscope?
Light Microscopes are limited by the physics of light to
500x or 1000x magnification and a resolution of 0.2
micrometers.
In the early 1930's there was a scientific desire to see the
fine details of the interior structures of organic cells
(nucleus, mitochondria...etc.).
This required 10,000x plus magnification which was just not
possible using Light Microscopes.

6. © 2013 FEI
Comparing
Microscopes
LIGHT MICROSCOPE
ELECTRON
MICROSCOPE
Use of vacuum No vacuum
Entire electron path from
gun to camera must be
under vacuum
The source of
illumination
The ambient light
source is light for the
microscope
Electrons are used to
“see” –
light is replaced by an
electron
gun built into the column
The lens type Glass lenses Electromagnetic lenses
Magnification
method
Magnification is
changed by moving the
lens
Focal length is charged by
changing the current
through
the lens coil
Viewing the
sample
Eyepiece (ocular)
Fluorescent screen or
digital camera

7. TEM instrument

9. Sample Preparation
• The TEM sample should be thin.
• Proper grinding and polishing removes damaged or
deformed surface material.
• Plastic deformation can introduce unwanted
structural defects in the microstructure that are
visible in TEM images.

10. Sample preparation
Sample Preparation

11. • Ultrasonic disk cutting: Ultrasonic disk cutting is
common sequence of preparation techniques For most
electronic materials.
• Dimpling: Dimpling is a preparation technique that
produces a specimen with a thinned central area and
an outer rim of sufficient thickness to permit ease of
handling.
• Ion milling : In this process, charged argon ions are
accelerated to the specimen surface by the application
of high voltage.
Technique of preparation sample

12. Example of TEM image
TEM image of ZnO
nanotubes
TEM image of CdSe-
graphene composite

13. Limitation
• Sample preparation is difficult.
• Potential can damage sample.
• Sample must be free from Water.
• The field of view is relatively small.
• Sample preparation is time consuming process.

14. Conclusion
• Sample Preparation is very important for
TEM.
• Tem instruments should be operate very
carefully.
• Very important Information we get From
TEM.

15. References
• Introduction to Nanoscience(Gabor L.Hornyak)
• Transmission electron microscopy, David B. Williams and C. Barry
Carter (Plenum, 1996)
• Electron microscopy of thin crystals, Peter Hirsch (Butterworths, 1965)
[2] R.F. Egerton. Electron Energy-Loss Spectroscopy in the Electron mics.
• [3] M.Von Heimendahl, W.Bell, G.Thomas. Applications of Kikuchi line
Analyses in Electron Microscopy. Journal of Applied Physics 35 (1964)
• [4] C. Richard Brundle, Charles A. Evans Jr, Shaun Wilson. Encyclopedia of
• materials characterization, Butterworth-Heinemann publications, 1992.
• [5] Joachim Mayer, Lucille A.Giannuzzi, Takeo Kamino, and Joseph Michael.
• [6]http://www.sciencedirect.com/science/article/pii/S1386142514011809
# (Paper had been accepted at July 29, 2014)
• [7]http://www.tandfonline.com/doi/abs/10.1080/1536383X.2014.885954
#.VKjpr8lYi-U (Paper had been accepted at January 17, 2014)

16. THANK YOU