| Autor: |
Renaat Gijbels, André Van Daele, Willem Jacob, Vladimir P. Oleshko |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Modern Developments and Applications in Microbeam Analysis ISBN: 9783211831069 |
| DOI: |
10.1007/978-3-7091-7506-4_12 |
| Popis: |
The combination of cryo-electron spectroscopic imaging (ESI)/electron energy-loss spectroscopy (EELS) and cryo-energy-dispersive X-ray (EDX) analysis in the scanning transmission (STEM) mode was applied for the characterization of Ag(Br, I) nano- and microcrystals. Combined qualitative silver and halide distributions were obtained by ESI (a three-window method) and by EDX/STEM including a high-magnification mapping of nanocrystals. A low-loss fine structure in EEL spectra between 4 and 26eV was attributed to excitons and plasmons possibly super-imposed with interband transitions and many-electron effects. Contrast tuning under energy-filtering was used to image electron excitations in the silver halide particles. The real and imaginary parts, e1 and e2, of dielectric permittivity were determined by means of a Kramers-Kronig analysis. A proposed assignment of exciton peaks based on calculations of electronic band structure of silver halides is discussed. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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