EELS: Principles, instrumentation, techniques and illustrative examples

Electron energy-loss spectroscopy (EELS) is the most powerful of the TEM-based analytical techniques for structural and chemical composition studies at the (sub)nanometer/atomic scale, and is therefore well suited to investigate individual nanostructures. The last two decades, TEM have undergone a large number of improvements allowing ~ 10 meV energy resolutions for a close to one angstrom electron beam. These performances offer new possibilities for probing the optical, dielectric and electronic properties of nanomaterials with unprecedented spatial information, as well as for studying the atomic configuration of nanostructures. In this lecture, I will introduce this technique and I will present a selection of the recent works involving all the above mentioned matters. These works will concern the study of the atomic structure & configuration of nanostructures as well as the opto-electronic properties studies carried out via EELS measurements of different kind of (nano)materials. These works will illustrate the excellent capabilities offered by the use of this technique.