MSE Seminar: Dr. Nasim Alem, The Pennsylvania State University
Wednesday, October 26, 2022
3117 Computer Science Instructional Center (CSI) Bldg # 406 and Via Zoom
Title: Probing nanostructured materials atom by atom: An aberration-corrected electron microscopy study
Abstract: Defects and interfaces can have a profound effect on the macroscale physical, chemical, plasmonic, and electronic properties of nanostructures. They can lead to local structural distortions and a different electronic structure. They can give rise to excess potential and novel optical and electronic properties. While defects and interfaces have been a well-studied subject for decades, little is known about their local atomic and electronic structure, sub-Ångstrom structural distortions within their vicinity, and their stability and transition dynamics under extreme conditions. Using ultra-high-resolution aberration-corrected Scanning/Transmission Electron Microscopy (S/TEM) imaging and monochromated electron energy loss spectroscopy (EELS), this talk will present our recent efforts on the determination of the defect chemistry and sub-Ångstrom relaxation effects at the defect sites and interfaces in novel nanostructures such as 2D crystal heterostructures and complex oxide systems among other novel nanostructures. In addition, we explore stability and transition dynamics of defects and interfaces under thermal or electrical biasing and their localized surface plasmon resonances (SPRs) at the nanoscale regime via energy filtered mapping. Understanding and nanoengineering the chemistry, size, and geometry of nanostructures is the key to produce more efficient nanostructures in energy storage, electronic, and optoelectronic applications.
Bio: Nasim Alem is a McFarlane associate professor of Materials Science and Engineering at the Penn State University. Nasim received her B.S. degree in Metallurgical Engineering from Sharif University of Technology, Tehran, Iran and her M.S. degree in Materials Science and Engineering from Worcester Polytechnic Institute. She received her PhD from the Materials Science Department at Northwestern University. Nasim was a postdoctoral researcher at the Physics Department at University of California Berkeley and National Center for Electron Microscopy (NCEM) at Lawrence Berkeley National Lab before joining Penn State in 2013. Her awards include NSF CAREER award, Fulbright visiting scholar award, and NCEM young investigator fellowship. Alem group research is focused on probing the atomic and chemical structure of the defects, edges, grain boundaries, and interfaces and their stability and transition dynamics using scanning/transmission electron microscopy imaging and spectroscopy.