ChEMS Seminar: Polarization-enabled Electronic Properties of Hybrid 2D-ferroelectric Structures

Abstract: In recent years there has been an unprecedented interest in various two-dimensional (2D) materials that often possess unique physical and chemical properties that cannot be found in their three-dimensional counterparts. An important advantage of 2D materials is the fact that due to their planar morphology they can be easily integrated with other 2D materials and functional films, resulting in multilayered structures with new properties. In particular, there was a considerable interest in a novel type of electronic devices, in which graphene, a 2D carbon material, was coupled with different ferroelectric (FE) materials. Electrically switchable ferroelectric polarization opens a possibility of electrical control of the functional properties of the adjacent graphene layer.

In this presentation, Gruverman will discuss implementation of the hybrid electronic devices comprising 2D materials and FE thin films (2D-FE) that exhibit polarization-controlled non-volatile modulation of the electronic transport. While many 2D materials can be considered in conjunction with FE materials, this talk primarily focuses on the use of graphene and transition metal dichalcogenide MoS₂. Specifically, it will demonstrate how polarization reversal can modulate (1) the in-plane transport of the interfacial conducting channel in the FE field effect devices, and (2) the perpendicular-to-plane tunneling conductance in the FE tunnel junction devices. Gruverman will demonstrate that interface engineering is a critical component determining the functional properties of these devices. A simple phenomenological modeling is developed to predict how the interface chemistry affects the electronic and transport properties of the 2D-FE structures.

Bio: Alexei Gruverman is a Charles Bessey Professor in the Department of Physics and Astronomy, University of Nebraska-Lincoln. He received his Ph.D. degree in solid state physics from the Ural State University in Ekaterinburg, Russia. His research interests are in the field of scanning probe microscopy of functional materials, electronic phenomena in ferroics and information storage technologies. Prior to joining UNL in 2007, he held research scientist positions at the Joint Research Center for Atom Technology in Tsukuba, Japan, and at Sony Corp., Yokohama, Japan, and a research professorship position at North Carolina State University. While working in Japan, he pioneered the SPM-based method for non-destructive high-resolution imaging of ferroelectric domains in thin films and memory devices - an approach now known as Piezoresponse Force Microscopy (PFM). Gruverman has co-authored over 180 papers in peer-reviewed international journals (including Science, Nature Materials and Physical Review Letters), which are cited more than 7000 times, a number of book chapters and review articles and has edited three books and several special journal issues on ferroelectricity. He serves as an associate editor for the IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. He is a recipient of the 2004 Ikeda Foundation Award and ISIF 2010 Outstanding Achievement Award, and is a Fellow of the American Physical Society and an International Fellow of the Japan Society of Applied Physics. Among his most important scientific accomplishments is the development of PFM, manipulation of ferroelectric domains at the nanoscale, development of an approach for fast-switching dynamics in ferroelectric capacitors, demonstration of the tunneling electroresistance effect in ferroelectrics, and nanoscale studies of electromechanical behavior of biological systems.

Host: Xiaoqing Pan