Practical Electron Microscopy and Database

An Online Book, Second Edition by Dr. Yougui Liao (2006)

Practical Electron Microscopy and Database - An Online Book

Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix

EELS Analysis of Nanometer Sized Objects

If the TEM sample is made of small particles, the particles can be dispersed in methanol and then drop and dry on a lacey C coated Cu TEM grid. EEL spectra can be obtained from the thin areas of the particles, typically <50 nm thick, overhanging holes in the lacy C film.

For EELS analysis of nanometer sized objects, contribution from the surface- and interface-related excitations may be predominant in their dielectric responses due to their large surface to volume ratio. [1] For instance, the individual nanotube can be studied by VEELS.

To obtain reliable structural data from the nano-structures (e.g. nanoparticles and nanotubes) through EELS measurements, any change in morphology must be negligible during the data acquisition. The electron beam can damage the nano-structures due to inelastic scattering in a number of ways:
         i) Surface sputtering/knock-on,
         ii) Bulk and surface diffusion,
         iii) Possible heating of thermally isolated metallic nanoparticles.
         

 

[1] Z. L. Wang, Micron 27, 265 (1996).