GÖZDE ARIBAL

20823751

AYKUT BİLİR

20823842

BORGA DERBENT

20823966

• 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

• 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

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.

Figure 1

• James Hillier

• RF Baker in the mid 1940s

• Research 1990s due to

advance in microscope

instrumentations and

vacuum technology

• 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

A typical EELS spectrum from an thin film

Figure 2

• Magnetic field is between two parallel

plates.

• Objective aperture

• Specimen

• Lens

• Collector aperture

• Figure 3

Photograph of the first electron microanalyzer (Hiller and Baker 1944)

• The measurements of

a) Local properties

b) Including specimen thickness

c) Mechanical and electronical

d) Chemical composition

• Higher core-loss signal

• Higher ultimate spatial resolution

• Absolute, standardless quantification

• Structural information available

• Higher spectral background

• Very thin specimen needed

• Possible inaccuracy in crystals

• More operator intensive

Table 1.Comprasion between EELS and EDX.

Table 2. X-ray fluorescence yield for K-,L- and M-

shells as a function of atomic number, from Krause (1979)

• Thickness measurements

• Pressure measurements

• Analytical electron microscopy (AEM)

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.

1) Journal de Physique IV , Colloque C7 ,

supplément au journal de physique III ,Volume

3

2) R.F. EGERTON Electron Energy Loss

Spectroscopy in The Electron Microscope 3.

Edition

3) Yüksek Lisans Tezi NANO ÖLÇEKLİ VANANYUM

OKSİT İNCE FİLMLERİN YAPISAL VE

ELEKTRİKSEL KARAKTERİZASYONU Ogeday

ÇAPAR