Four‐Dimensional Materials Science
Department of Materials Science and Engineering
University of Illinois, Urbana‐Champaign
Thursday, January 28, 2016
Engineering Research Center (ERC) 490, Tempe campus [map]
Many technologically important materials possess complex nanostructures and structure dependent properties that require time-dependent three-dimensional (3D) structure determination and thus the need for four-dimensional (4D) material science. Transmission high energy electron diffraction (THEED) and the related imaging are appropriate techniques for 3D nanostructure determination because they are highly sensitive to local atomic structure. Compared to X-ray diffraction, the small interaction volume in THEED allows for high spatial resolution. However, because of the material dependent strong electron-matter interaction, a general approach to 3D structure analysis is still a challenge. Prof. Jian-Min Zuo will describe a TEM based scanning electron nanodiffraction (SEND) technique for determining complex nanostructures at the resolution of few nm. In SEND, diffraction patterns are recorded by scanning the beam using the built-in TEM deflection coils and automatic camera readout. In a field emission gun TEM, SEND can be performed using electron beams of ~1 nm in full-width at half-maximum (FWHM) and tens of pA beam current. Electron diffraction pattern indexing is achieved by a combination of correlation analysis of the recorded diffraction patterns, diffraction peak search and peak indexing using both length and angle information. By coupling with a tomographic holder, SEND can be performed in 3D with large sample tilts and thus the opportunity for the determination of 3D nanostructures at nanometer resolution with crystallographic information (Figure 1). Future research directions include coupling of 3D structure determination with in-situ experiments, electron spectroscopy and atomic resolution imaging for a complete approach to 4D materials science.
Jian-Min Zuo received his Ph.D. in Physics from Arizona State University in 1989. He then took a three- year postdoctoral fellowship at the National Science Foundation center for high resolution electron microscopy and the Physics department at ASU. During this time he co- authored a book on electron microdiffraction with Prof. John Spence.
Prior to joining the faculty at the University of Illinois in 2000, he was a research scientist in Physics at ASU and a visiting scientist to a number of universities and institutes in Germany, Japan and Norway. At Illinois, Prof. Zuo has developed research programs focused on structure and property relationships in a range of materials, including metal nanoparticles, semiconductors, electroceramics, oxide interfaces, and nanotubes. Prof. Zuo also has developed an ultrafast electron diffraction facility and atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy using the aberration corrected electron microscope at the Center for Microanalysis of Materials.
Prof. Zuo has published more than 180 papers in scientific journals and several invited book chapters on electron diffraction and diffractive imaging. His honors include the American Physical Society Fellow, Ernst Ruska Prize of German Microscopy Society, NSF career award, Burton Award of Microscopy Society of America.