Physics Colloquium

Electron Diffraction, from Quantum Mechanics to Imaging Proteins and FinFET Devices

Presented by Jian-Min Zuo, University of Illinois

Abstract

Electrons diffract like X-rays and neutrons, except that the electron wavelength is very small (of the order of a few picometers), and the electron scattering cross-section is much larger, about a million times that of X-rays. Inside a transmission electron microscope (TEM), the electron beam can be focused down to < 1 Å in diameter with the current reaching hundreds of picoamps (1 pA = 6.3x10˄⁶ e/s), so the scattering power of an electron beam is larger than that of a synchrotron. Since electron diffraction was discovered by Davisson and Germer, and Thomson and Reid, in 1927, transmission electron diffraction and the related electron imaging have developed into powerful tools for the analysis of materials, such as proteins and transistor devices.

This talk will introduce the basic quantum property of electrons, that is coherence, the manifestation of coherence, that is diffraction, and how the combination of electron coherence with fast electron detectors has made electron diffraction an exciting development story for the coming decade.