Presentation on theme: "ELECTRON ENERGY LOSS SPECTROSCOPY"— Presentation transcript:
1 ELECTRON ENERGY LOSS SPECTROSCOPY GÖZDE ARIBALAYKUT BİLİRBORGA DERBENT
2 CONTENTS What is the EELS ? The process of historical development How does it work ?Components and propertiesWhy is it used ?Advantages and DisadvantagesCompare with EDXApplicationsSummaryReferences
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 distributionCapable of giving structural and chemical informationElectron spectrometer
4 Figure 1High-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 HillierRF Baker in the mid 1940sResearch 1990s due toadvance in microscopeinstrumentations andvacuum technology
6 HOW DOES IT WORK ? Can be obtained experimentally In elastic scattering of X-ray photons or optical measurementsChange in momentum and direction of propaganationChange in internal degrees of freedom
7 A typical EELS spectrum from an thin film Figure 2A typical EELS spectrum from an thin film
8 COMPONENTS AND PROPERTIES Magnetic field is between two parallel plates.Objective apertureSpecimenLensCollector aperture
9 Photograph of the first electron microanalyzer (Hiller and Baker 1944) Figure 3Photograph of the first electron microanalyzer (Hiller and Baker 1944)
10 WHY IS IT USED ? The measurements of Local properties Including specimen thicknessMechanical and electronicalChemical composition
11 ADVANTAGES Higher core-loss signal Higher ultimate spatial resolution Absolute, standardless quantificationStructural information available
12 DISADVANTAGES Higher spectral background Very thin specimen needed Possible inaccuracy in crystalsMore operator intensive
13 Table 1.Comprasion between EELS and EDX. COMPARE WITH EDXTable 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 SUMMARYElectron 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 REFERENCESJournal de Physique IV , Colloque C7 , supplément au journal de physique III ,Volume 3R.F. EGERTON Electron Energy Loss Spectroscopy in The Electron Microscope 3. EditionYüksek Lisans Tezi NANO ÖLÇEKLİ VANANYUM OKSİT İNCE FİLMLERİN YAPISAL VE ELEKTRİKSEL KARAKTERİZASYONU Ogeday ÇAPAR