14.11.2018

Electron diffraction in the scanning electron microscope: an atom's perspective – seminar


The Environmental Seminar on Solid State Physics as well as Seminar of the AGH UST Academic Centre for Materials and Nanotechnologies will be held on 14th November 2018, at 9.00 am.

A lecture titled “Electron diffraction in the scanning electron microscope: an atom's perspective” will be given by dr Habil Aimo Winkelmann (Laser Zentrum Hannover, Germany).

Venue: Academic Centre for Materials and Nanotechnology AGH UST (Kawiory 30 Street, building D-16, auditorium room 1.02A)

Abstract

The Scanning Electron Microscope (SEM) is a powerful tool to investigate a wide variety of samples on length scales ranging from centimeters down to the nanometer region. The polycrystalline microstructure of many technological, geological, and even biological materials calls for suitable microcrystallographic analysis methods in the SEM. Application examples include steels, metal alloys and semiconductors, but also meteorites, chiral quartz crystals, and egg-shells of dinosaurs and birds. In this talk, the two main sources of crystallographic information in the SEM will be discussed: Diffraction effects of electrons in the primary SEM beam lead to the formation of the "electron channeling patterns" (ECP), while diffraction of inelastically backscattered electrons is used in the method of "electron backscatter diffraction" (EBSD). In both methods, very characteristic diffraction patterns play a central role, the so-called "Kikuchi patterns". By adopting the perspective of an atom in a crystal, the beautiful geometry and the instructive physics of Kikuchi pattern formation will be explained and a selection of possible applications will be discussed.