1. ELECTRON ENERGY LOSS SPECTROSCOPY
GÖZDE ARIBAL
AYKUT BİLİR
BORGA DERBENT

2. CONTENTS What is the EELS ? The process of historical development
How does it work ?
Components and properties
Why is it used ?
Advantages and Disadvantages
Compare with EDX
Applications
Summary
References

3. WHAT IS EELS ? Analytical technique Quantitative analysis
Analysis of the inelastic scattering suffered by the transmitted electron beam with measurement of the electron energy distribution
Capable of giving structural and chemical information
Electron spectrometer

4. Figure 1
High-resolution electron energy loss spectroscopy (EELS) is a high-sensitivity, non-destructive technique for the study of surface and adsorbate vibrations and low-energy electronic excitations.

5. THE PROCESS OF HISTORICAL DEVELOPMNET
James Hillier
RF Baker in the mid 1940s
Research 1990s due to
advance in microscope
instrumentations and
vacuum technology

6. HOW DOES IT WORK ? Can be obtained experimentally
In elastic scattering of X-ray photons or optical measurements
Change in momentum and direction of propaganation
Change in internal degrees of freedom

7. A typical EELS spectrum from an thin film
Figure 2
A typical EELS spectrum from an thin film

8. COMPONENTS AND PROPERTIES
Magnetic field is between two parallel plates.
Objective aperture
Specimen
Lens
Collector aperture

9. Photograph of the first electron microanalyzer (Hiller and Baker 1944)
Figure 3
Photograph of the first electron microanalyzer (Hiller and Baker 1944)

10. WHY IS IT USED ? The measurements of Local properties
Including specimen thickness
Mechanical and electronical
Chemical composition

11. ADVANTAGES Higher core-loss signal Higher ultimate spatial resolution
Absolute, standardless quantification
Structural information available

12. DISADVANTAGES Higher spectral background Very thin specimen needed
Possible inaccuracy in crystals
More operator intensive

13. Table 1.Comprasion between EELS and EDX.
COMPARE WITH EDX
Table 1.Comprasion between EELS and EDX.

14. Table 2. X-ray fluorescence yield for K-,L- and M shells as a function of atomic number, from Krause (1979)

15. APPLICATIONS Thickness measurements Pressure measurements
Analytical electron microscopy (AEM)

16. SUMMARY
Electron energy-loss spectroscopy (EELS) is an analytical technique that measures the change in kinetic energy of electrons after they have interacted with a specimen.

17. REFERENCES
Journal de Physique IV , Colloque C7 , supplément au journal de physique III ,Volume 3
R.F. EGERTON Electron Energy Loss Spectroscopy in The Electron Microscope 3. Edition
Yüksek Lisans Tezi NANO ÖLÇEKLİ VANANYUM OKSİT İNCE FİLMLERİN YAPISAL VE ELEKTRİKSEL KARAKTERİZASYONU Ogeday ÇAPAR

18. THANK YOU !